Prime Minister Boris Johnson called for a united effort to tackle spiking coronavirus infection rates, as 56 million people in England went into a second lockdown but with the public weary of restrictions and fearing for their livelihoods.

Renewed stay-at-home restrictions and business closures came into force Thursday and are set to last for four weeks yet have been met with scepticism that they can halt the worst death toll from the virus in Europe.

"While it pains me to have to ask once again for so many to give up so much, I know that, together, we can get through this," said Johnson, whose government sets health policy in England.

"We can do this, we will do this by December 2nd," he told a news conference, promising that compliance could see people enjoy "as normal a Christmas as possible". 

The latest lockdown came into force at 0001 GMT Thursday and by daybreak had turned normally bustling cities into ghost towns.

"You can't imagine from yesterday to today how different it is. It's completely dead now," Maria Belkihel, 42, told AFP in London's best-known shopping spot, Oxford Street.

The Bank of England unveiled an extra £150 billion ($195 billion) in economic support, on top of new Treasury measures to subsidise the wages of furloughed workers until March 2021.

Johnson said the package showed his government will "continue to support people affected by these new restrictions".

The government also announced passengers arriving in Britain from Germany and Sweden must self-isolate for 14 days from 0400 GMT Saturday, the latest countries removed from its coronavirus travel list.

Meanwhile, Foreign Secretary Dominic Raab began self-isolating after coming into contact with someone who tested positive for Covid-19, a spokesman said. 

"He will continue to work remotely during this time," he added.

- Economic concerns mounting -

Johnson abandoned a recently introduced system of regional curbs and announced the shutdown after dire warnings that hospitals could soon be overwhelmed with Covid-19 cases. 

Simon Stevens, the head of the state-run National Health Service (NHS) in England, urged compliance and warned: "This second wave of Covid is real and it is serious."

"Today's infection is the intensive care order book for a fortnight's time," he added, noting the total number of patients admitted to hospital had shot up from below 500 in early September to more than 11,000.

Opinion polls suggest overall public backing for the revived stay-at-home policy.

But concerns are mounting about the impact on the economy and mental health, and dozens of lawmakers in Johnson's ruling Conservative party rebelled against the new measures during a vote in parliament Wednesday.

On Thursday night, demonstrators gathered in central London to protest the new lockdown, with police saying they had arrested more than 100, the majority for breaching the new restrictions.

To avoid extending the lockdown, Johnson is pinning his hopes on an ambitious new programme of Covid testing to detect and isolate infected people, starting with a city-wide trial launching in Liverpool on Friday.

Around 2,000 military personnel are being mobilised to help in the pilot, which will identify positive cases even in people without symptoms.

The government has spent £12 billion on testing programmes, but researchers say most members of the public are failing to isolate or report their contacts fully.

- '100 percent culpable' -

Britain has recorded nearly 48,000 deaths linked to the coronavirus from more than one million positive cases: 492 deaths were recorded on Wednesday -- the highest since May.

As in March, when the first shutdown was ordered, critics accuse Johnson of failing to heed warnings by government scientists and acting too late.

The new restrictions bring England into line with other parts of the UK, which have their own devolved governments, and with nations in Europe including France.

They include a return to working from home where possible and the closure of all non-essential shops and services. 

Schools will remain open. Exemptions include outdoor exercise and visits to the doctor or pharmacy.

Michael Eppy, a public relations expert on his way to a medical appointment, said: "I don't think anyone is particularly happy about the lockdown." 

Doubting Johnson's assurances of a four-week limit, Eppy, 35, said: "However long this lockdown lasts, it is this government that is 100 percent culpable."