THE Prime Minster has said complacency could be 'fatal' as he announced all travel corridors to the UK will close from 4am on Monday.

Speaking from Downing Street as part of the government's daily coronavirus briefings, Boris Johnson said now was not the time for relaxing restrictions, with substantial fines for those failing to comply.

He said: "It would be fatal if this sense of progress were now to breed any kind of complacency because the pressures on the NHS are extraordinary.

"On Tuesday we saw 4134 new admissions to hospital no a single day, the highest of any point during the pandemic.

"There are now than 37,000 Covid patients in hospital around the UK."

The Prime Minister went on to say how cancer treatments were being cancelled, despite the best efforts of NHS staff, as well the sight of Ambulances queuing outside hospitals with intensive care units 'spilling over' into adjacent wards.

There had been 55,761 new positive cases since yesterday, with 1,208 deaths within 28 days of a positive Covid test.

"This is not the time for the slightest relaxation of our national resolve and our individual efforts," he said.

"Please remember that this disease cannot just be passed on by standing too close to someone in a supermarket queue, but also by handling something touched by an infected person.

"Remember also that one in three people don't have Covid symptoms.

"Washing you hands now is an important now as it has ever been."

Explaining how additional steps needed to be taken on allowing people to enter the country, the PM announced that in addition to flights from South America and Portugal being banned yesterday, all travel corridors will be closed temporarily from 4am on Monday.

He said: "This means that if you come to this country you must have proof of a negative Covid test you have taken within 72 hours of leaving.

"You must have filled in your passenger locator form and your airline will ask for proof of both before you take off.

"This will also be checked when you land and you will face substantial fines.

"Upon arrival you must also quarantine for ten days and not leave your home for any reason at all or take another test on day five and wait for proof of another negative result.

"We will be stepping up our enforcement, both at the border and in country.

"It's vital to take these extra measures now."

He went on to say more than 3.2 million people had now been vaccinated across the country with a quarter of a million people vaccinated on Thursday alone, and that 45 per cent of those aged over 80 had now received their vaccine.