Some 2.5 million Queenslanders are being plunged back into lockdown, Greater Brisbane has been declared a national hotspot and other states are imposing travel restrictions – all due to a single new community case of COVID-19.

The new case, a woman in her 20s, works as a casual cleaner at a quarantine hotel in Brisbane and visited various stores and travelled on public transport while infectious.

It was revealed late yesterday that the woman was infected with a new COVID-19 variant originating from the United Kingdom.

Even Prime Minister Scott Morrison, who has previously criticised harsh lockdown measures such as those seen in Victoria, has backed the snap lockdown and border measures.

So just what about this new case has health authorities so worried?

READ MORE: Prime Minister says Brisbane is in a 'serious situation'

The new COVID-19 strain spreads more quickly

Like other viruses, the SARS-CoV-2 virus that causes COVID-19 is constantly mutating.

Most of the time, these mutations are useless but every so often, a mutation will prove advantageous – making the virus more transmissible or more deadly.

This new COVID-19 variant, known as VUI–202012/01 or lineage B.1.1.7, has an unusual number and combination of mutations.

It carries 14 defining mutations, including seven in the spike protein – the protein that mediates entry of the virus into human cells.

In the UK, where the virus originated and has since become rampant, the new strain has since been demonstrated to be up to 70 per cent more infectious than previous variants.

This means it could increase the R rate (Reproduction rate) of the virus by around 0.4.

In more positive news, it does not appear to be more likely to result in severe infection or less effective against current vaccines.

Why Australian health authorities are on edge

The new variant's increase transmissibility means that COVID-safe practices such as mask use and social distancing which have proven effective in containing previous small outbreaks across Australia may not stand up against the new strain.

This was a point made clear by Queensland's Chief Health Officer Dr Jeanette Young this morning.

"We have all seen other states – and indeed ourselves – deal with other cases and we've allowed things to continue and that has taken us then weeks to get on top of it. But we got on top of it," she said.

"I'm really concerned that if we were to have cases from this very, very contagious, infectious virus, we wouldn't be able to get on top of it.

"Once it is spread, it will be too late to act."

How the Brisbane cleaner acquired the infection has also caused concern, with fears the virus managed to defeat stringent health and safety protocols in place at Brisbane's quarantine hotels.

The woman is the first quarantine worker to be infected in Queensland and health authorities have stressed she "did everything right".

How did the new strain reach Australia?

As with all recent outbreaks in Australia, the latest Brisbane case was acquired through returned travellers in hotel quarantine infected with the virus.

The B.1.1.7 strain was first identified in the English county of Kent on September 20, but it wasn't announced by UK health secretary Matt Hancock until December 14.

It has since become the dominant strain in many parts of the United Kingdom, and is now spreading rapidly across the globe.

At least 56 cases of the variant have been confirmed in the United States – where fewer than one per cent of cases are genome sequenced – as well as many across Europe and Asia.

Today, Mr Morrison confirmed that 80 per cent of the countries that Australians are returning from have confirmed cases of the strain.

"This strain is likely to become, in the very near future, the dominant strain (worldwide), as it largely already is in the UK," Scott Morrison said.

"So the idea that it somehow can be contained just out of the United Kingdom is a false hope."

So will whole cities lock down now every time there's a case?

That remains to be seen, but Mr Morrison isn't ruling it out.

"We will see – that's my honest answer," he told today's press conference.

"This is a very significant issue and we will deal with it, and we will learn what we need to learn from it – and that is what will guide further actions."

Further measures have been put in place in attempt to limit breaches of Australia's program for returning travellers from overseas, including mandatory masks on planes and reducing the number of arrivals coming in.

It is hoped that this will ease pressure on the quarantine hotels and lessen the likelihood of infection breaches.

However, if the new B.1.1.7 virus does indeed come to dominate worldwide, the Brisbane woman is unlikely to be the last case to escape Australia's infection protocols.

A property in a normally quiet South Australian neighbourhood was stormed by heavily armed police today, where they allegedly uncovered prohibited drugs, stashes of money and an explosive device.

A man and woman who live at the Modlavia Walk property in Osborne, about 21 kilometres north-west of the Adelaide city centre, were quickly arrested.

Neighbours say they were concerned by the raid on their street but are grateful that police acted when they did.

"They (police) flung the garage up, smashed the door in and yeah got him (the man), heard them yelling, 'hands up'," a local resident said.

The woman was shortly after quizzed by police before being loaded into a car flanked by detectives and taken away.

"They've been coming in all morning heaps of them and started searching the place," the resident said.

With the help of a drug detection dog, officers allege they found a haul of cannabis and methamphetamine at the property.

Police said they allegedly discovered a pipe bomb which was safely removed by the Bomb Response Unit.

Leaving no stone unturned, officers also discovered a large amount of cash and a number of stolen items.

Police charged the pair with a number of offences including trafficking a controlled drug, money laundering and possessing an explosive device.

The woman was released late today while the man was refused bail and will face court on Monday.

An aunty of Waihī Beach shark attack victim Kaelah Marlow says the whole family are in “shock” after the 19-year-old’s death.Marlow was dragged from the water alive after the attack but paramedics administered CPR on the…

Brisbane has now been thrust into a three-day lockdown after Scott Morrison declared the area a hotspot amid "serious" threats of an outbreak of UK's mutant strain.

The prime minister said the Queensland government made a "wise decision" to enforce the restrictions, which came into force 6pm today, after a quarantine hotel worker tested positive to the highly contagious UK strain of COVID-19.

"It moves so quickly far more quickly than previous strains of the virus," Mr Morrison said today.

LIVE UPDATES: Brisbane to enter three-day lockdown as UK virus case diagnosed

"That means we need to give our contact tracers a head start to ensure they can track down all of the contacts from this individual."

The prime minister also revealed Greater Brisbane will be declared a Commonwealth Coronavirus Hotspot region from today.

The ruling applies to the Brisbane, Logan, Moreton Bay and Redlands regions of the city.

"Our message to Australian in those areas is stay where you are," Mr Morrison said.

"Don't go anywhere and don't go home to another state or any other part of your state.

"Over the next few days, stay where you are."

EXPLAINER: Brisbane lockdown – what you can and can't do

Greater Brisbane will enter a three-day lockdown this evening to prevent the spread of the UK COVID-19 strain.

The areas included in the lockdown are Metro North, Metro South and West Moreton.

From 6pm tonight, Brisbane, Logan, Ipswich, Moreton, and Redlands will be under the same restrictions introduced in March.

"We know that this UK strain is highly infectious," Premier Annastacia Palaszczuk said.

"It is 70 per cent more infectious (than previous strains) and we are going to go hard and we are going to go early to do everything we can to stop the spread of this virus."

Lockdown restrictions have also been extended to anyone who has visited Greater Brisbane area since January 2, regardless of where they are in the state.

"Think of it as a long weekend at home. We need to do this," Ms Palaszczuk said.

"If we do not do this now, it could end up being a 30-day lockdown."

https://twitter.com/AnnastaciaMP/status/1347309459891109888?ref_src=twsrc%5Etfw

Queensland has reported nine new cases of COVID-19 in hotel quarantine.

More than 13,000 people were tested for the virus overnight, however Ms Palaszscuk urged more people to come forward.

"I want to thank people who have come out in their thousands to get tested but we want more to get tested, we want to see higher testing rates especially in the areas we outlined yesterday," she said.

READ MORE: Victoria records zero local COVID-19 cases, one detected in returned traveller

People in the designated lockdown areas will only be able to leave their home for essential reasons including providing or receiving healthcare or support for a vulnerable person, essential shopping within their local area and exercise in your local neighbourhood.

In addition, people will be required to wear a mask while outside their homes.

It is the first time a mask mandate has been enforced in Queensland since the beginning of the pandemic.

"I know this will be tough on businesses over the next few days but I am thinking about your long-term futures as well. So it is incredibly important that we take these strong measures," Ms Palaszczuk said.

Ms Palaszczuk said the government has declared Brisbane and Greater Brisbane as a COVID-19 hotspot.

"It is incredibly important in this time to stop the spread of this infectious UK strain, we must act immediately, we must act strongly, and we have taken those strong measures today," she said.

The state's Chief Health Officer Dr Jeanette Young said Queenslanders "can't relax" until all cases of the UK virus are found.

"We need to act really, really fast. We need to find every single case now. We need to find every person who might have had contact with that lady now – find them and get them into quarantine. That's what we've got to do over the next three days," Dr Young said.

"I have absolute confidence that we will do that."

For the next three days, funerals will be limited to 20 people, weddings to 10 people and people have been asked to limit any non-essential movement.

"We're asking people not to go to any non-essential businesses such as hairdressers, nail salons, etc, cinemas, gyms – all of those sporting activities over the weekend, organised community sport, all of that is just on hold," Dr Young said.

"We need to take a pause for the next three days and just see what this single case means."

Queenslanders who have visited hotspot areas and are now interstate have been asked to get tested if they develop any symptoms of COVID-19.

Queenslanders in Greater Brisbane have also been asked to avoid visiting vulnerable family members in aged care and hospitals.

Dr Young also urged people to avoid panic buying of essential goods ahead of tonight's lockdown.

Police will issue fines for people who break the new restrictions over the coming days.

Ms Palaszczuk said anyone who is currently on holiday outside the hotspot areas is allowed to return home, but they must remain for the next three days.

People planning to leave the Greater Brisbane area will not be permitted to do so.

"If you are in those Greater Brisbane areas and you may have planned a vacation over this weekend. I'm so sorry, but you will not be able to go. You will have to reschedule," she said.

A growing number of politicians – including from Democratic leadership – are calling for President Donald Trump to be removed from office either through impeachment or the 25th Amendment to the Constitution after a violent mob of Trump supporters stormed the US Capitol.

House Speaker Nancy Pelosi is the latest to push for immediate action, calling on Vice President Mike Pence to invoke the 25th Amendment.

"I join the Senate democratic leader in calling on the Vice-President to remove this President by immediately invoking the 25th amendment,' Ms Pelosi said a short time ago.

"If the Vice-President and Cabinet do not act, the Congress may be prepared to move forward with impeachment."

Her comments come after moves by the Democrats, and at least one congressional Republican. Republican Adam Kinzinger of Illinois, a frequent critic of the President, has called for the 25th Amendment to be invoked, saying in a video message on Thursday local time, "the President must now relinquish control of the executive branch voluntarily or involuntarily".

The top Democrat in the Senate has also embraced the 25th Amendment push.

Senate Democratic leader Chuck Schumer put out a statement on Thursday denouncing the "insurrection" at the Capitol "incited by the President," and saying, "This president should not hold office one day longer".

"The quickest and most effective way — it can be done today — to remove this president from office would be for the Vice President to immediately invoke the 25th amendment. If the Vice President and the Cabinet refuse to stand up, Congress should reconvene to impeach the president," he said in the statement.

Invoking the 25th Amendment would require Vice President Mike Pence and a majority of the Cabinet to vote to remove Mr Trump from office due to his inability to "discharge the powers and duties of his office" — an unprecedented step.

Other rank-and-file Democrats have urged impeachment in the wake of the mob violence at the Capitol that took place as a joint session of Congress met to count the Electoral Votes affirming President-elect Joe Biden's win amid false claims from Mr Trump that the election was rigged against him.

Four members of the progressive "squad" of Democratic lawmakers – Representatives Alexandria Ocasio-Cortez, Ilhan Omar, Rashida Tlaib and Ayanna Pressley — all spoke out in support of impeachment in the wake of the violent siege of the Capitol.

"I am drawing up Articles of Impeachment. Donald J. Trump should be impeached by the House of Representatives & removed from office by the United States Senate. We can't allow him to remain in office, it's a matter of preserving our Republic and we need to fulfill our oath," Ms Omar tweeted Wednesday.

"This is on Donald Trump, period. He called folks to D.C. and gave them marching orders. He needs to be impeached and removed immediately," Ms Tlaib tweeted Wednesday.

With Mr Biden's inauguration date fast approaching on January 20, it is highly unlikely that there would be adequate time or political will in Congress for any kind of impeachment effort.

Any 25th Amendment push is also unlikely to come to fruition with little time left before Mr Biden's inauguration. The calls in Congress, however, underscore the extent to which lawmakers are reeling and furious with the President in the wake of the devastation at the Capitol on Wednesday.

The Democratic-led House of Representatives impeached Mr Trump already in 2019. In order to remove a President from office through impeachment, the Senate must vote to convict after an impeachment trial. That did not happen in the Republican-controlled Senate where Mr Trump was ultimately acquitted.

After the pro-Trump mob was cleared from the Capitol, lawmakers reconvened late in the evening to continue the Electoral vote count. Congress completed the count and finalised Mr Biden's win in the early hours of Thursday morning, US time.

Earlier, Facebook CEO Mark Zuckerberg confirmed the social media platform will ban Mr Trump's account from posting for at least the remainder of his term in office and perhaps "indefinitely".

Major roads out of Brisbane were packed as residents drove away from the area's 6pm lockdown which is now in force.

Traffic had almost been brought to a standstill on the Bruce Highway, as thousands of residents tried to make their way to the Sunshine Coast.

Motorists travelling south to the Gold Coast on the M1 were warned traffic was slow through Springwood and Pimpama.

READ MORE: Prime Minister says Brisbane is in a 'serious situation' as he backs lockdown

https://twitter.com/RACQOfficial/status/1347386036192649220

Now restrictions are in force tonight, police have said they will launch a blitz to make sure drivers are following the health orders.

Gold Coast Police Chief Superintendent Mark Wheeler said officers would use number plate recognition technology to detect Brisbane drivers.

"I would ask everyone to do the right thing," he said.

"If you're from the Greater Brisbane area, just stay home for the weekend."

Brisbane Airport has also been busy, as travellers rush to get home to beat new border restrictions in other states and territories.

Western Australia, the Northern Territory, South Australia have all closed their borders to Greater Brisbane after the Federal Government declared it a COVID-19 hotspot.

The rush to leave the city comes as the Prime Minister urged residents to "stay where you are".

"Don't go anywhere and don't go home to another state or any other part of your state," Scott Morrison said.

"Over the next few days, stay where you are."

RELATED: Australia's domestic border restrictions explained: State-by-state breakdown

Greater Brisbane will enter a three-day lockdown this evening to prevent the spread of the UK COVID-19 strain.

The new restrictions come after a quarantine hotel cleaner from Algester tested positive to the virus yesterday.

From now, Brisbane, Logan, Ipswich, Moreton, and Redlands will be under the same restrictions introduced in March.

People in the designated lockdown areas will only be able to leave their home for essential reasons including providing or receiving healthcare or support for a vulnerable person, essential shopping within their local area and exercise in your local neighbourhood.

https://twitter.com/qldhealthnews/status/1347320522657316867

Anyone coming into Australia must first return a negative coronavirus test before departure, and masks will be mandatory on all flights going forward.

Prime Minister Scott Morrison announced these measures, along with the intent to reduce flight caps for international arrivals for the next month, today following National Cabinet.

The raft of new rules around travel are in direct response to the detection of the new highly-virulent UK strain of the virus in Australia.

READ MORE: Greater Brisbane to enter three-day lockdown after new locally acquired case

LIVE UPDATES: US Capitol Police officer dies; Nancy Pelosi calls for Trump to be removed or impeached

Mr Morrison said from today passengers and crew must wear masks throughout any domestic flight and inside all Australian airports.

Children under 12 and those with specific medical conditions are exempt from this rule.

Australian passengers and crew must also be masked on any international flights or in overseas airports.

International air crews must undergo a COVID-19 test in Australia every seven days, and will have their own specialist quarantine location, and are not allowed to move around.

"These measures, over the course of the next week, and the compliance arrangements that sit around that, will be put in place by the Commonwealth and the state governments," Mr Morrison said.

Alongside new rules for international travellers, Mr Morrison said there will be reduced caps on international travellers entering Australia.

These are as follows:

• NSW – 1505 travellers a week
• Western Australia – 512 travellers a week
• Queensland – 500 travellers a week
• Victoria – no change
• South Australia – no change (currently 490)

"That will be reviewed now by 15 February, not under the arrangement we previously had, which was at the end of this month," the prime minister said.

Greater Brisbane has been declared a COVID-19 hotspot on a Commonwealth level, meaning it will be recognised by every state and territory in the country. 

"The Brisbane hotspot, as we are declaring it at a Commonwealth level – it is different to a normal definition we'd apply to hotspots, but you've got to change the rules when there is new information and new uncertainties being introduced," Mr Morrison said.  

"And that is the case in relation to this strain. That applies to Brisbane, Logan, Moreton, Redlands, and Ipswich. This comes into effect at 6pm this evening." 

Following National Cabinet, Western Australia Premier Mark McGowan described the positive case of the mutant strain of COVID-19 in Brisbane as "extremely concerning".

"This is a dangerous situation, not only for Brisbane, but for the whole of Australia," Mr McGowan said.

As a result, a hard border with Queensland will be reinstated and will come into effect at midnight tonight.

Travel into Western Australia from Queensland will no longer be permitted, with some exemptions.

Premier Daniel Andrews has issued a stern warning for Victorians not to protest the day that divides the nation – Australia Day.

It comes as the traditional Australia Day parade has been ruled off the calendar this January 26.

Mr Andrews has urged people against gathering, regardless whether for celebrations or protests.

"It's not about what you're gathering for, it's about, are you gathering in a safe way?" Mr Andrews said.

"It (the Invasion Day march) is not a seated event and judgement from public health team – not politicians – was it couldn't be done safely."

Opposition leader David Davis labelled Mr Andrews' approach as a "clear double standard."

"It's a repeat of what happened in June with the (Black Lives Matter) march then," Mr Davis said.

But an "Invasion Day" dawn service will proceed, with the backing of Melbourne City Council.

"I don't believe the world should stop because of COVID we just have to do it differently," Jill Gallagher, Former Treaty Commissioner, said.

"It's still important to get message across about what Australia Day means to us as aboriginal people."

Outdoor gatherings in Melbourne are currently limited to 100 people, but exemptions can be granted for public events as long as organisers submit a COVID safe plan.

Everyone in attendance must be registered and they're required to maintain social distance.

"The dawn ceremony is a way of supporting an event that reflects that ancient Australian history," Melbourne Lord Mayor Sally Capp said.

The service at Kings Domain will be ticketed for 250 seated people with council organising QR codes and COVID marshals.

Intelligence have suggested protests are being planned by those on both sides of the political spectrum.

"There will be zero tolerance for any antisocial or criminal behaviour," a Victoria Police spokesperson said.