Watch: UK reports 44,917 COVID cases
It marks an 11 per cent rise on last Monday’s total of 39,705 - though deaths have fallen slightly from the 47 recorded a week ago.
The total number of fatalities now stands at 143,972, while 9,889,926 Britons have been infected.
Meanwhile, the latest figures for vaccination show that 237,995 people received their third dose on Sunday - up from last week’s total but far lower than the 463,064 Britons who received the booster jab on Saturday.
It means that a total of 15,331,311 people have now received a third shot, which ministers see as crucial to avoiding a return to restrictions during the Winter period.
Over-40s were on Monday urged to come forward to book a slot for their third jab, with some 500,000 people currently eligible for the booster.
Boris Johnson said the Government currently sees no need to introduce fresh restrictions - despite a concerning rise in infections across Europe.
Speaking at the CBI conference in South Shields, the Prime Minister said: “Of course we are concerned about the potential from that disease.
“You have got to be humble in the face of nature but at the moment we see nothing in the data to say that we need to move from plan A to plan B, or any other plan.
“The best single thing you can all do is get your booster. When you are called forward to get it, please do so.”
Elsewhere, a minister pledged to review England’s rules for international travel in January to help airlines “bounce back” from the financial damage brought by the pandemic.
Aviation minister Robert Courts said the Government would reassess regulations for people arriving in the country.
Despite an easing of the rules last month, even fully vaccinated travellers continue to be required to pay for a test when they enter the UK.
There are also complaints that the passenger locator form all arrivals must submit is too complicated.
“We all want to reduce not just testing but all the restrictive measures,” he told the Airlines 2021 conference in Westminster.
Watch: Professor on why Europe is seeing higher Covid rates than the UK