A further 1,631 deaths were reported on Tuesday, bringing the national total to 100,162. This figure stands at 103,602 where Covid-19 is mentioned on the death certificate.
Health secretary Matt Hancock said the UK’s death toll was "heart-breaking" and warned there was still "a tough period ahead".
Labour leader Sir Keir Starmer said the figure marked a "national tragedy" and was “a terrible reminder of all that we have lost as a country”.
Britain is the fifth country to record 100,000 virus-related deaths, after the United States, Brazil, India and Mexico, and by far the smallest. It stands alone with the highest daily death rate in the world.
The UK toll is more than twice as many people as were killed by German bombs in Britain in the 1940-41 Blitz, and 30,000 more than the total number of British civilians killed during the six years of World War Two.
More than a quarter of all UK deaths have been reported in the last month alone, the culmination of the government’s failed tier system, pre-Christmas mixing and the emergence of the new coronavirus variant, critics say.
Prime minister Boris Johnson has promised that a public inquiry will examine Britain's handling of the pandemic, though he has not said when it will start.
The government also said that, as of 9am on Tuesday, there had been a further 20,089 lab-confirmed cases of coronavirus in the UK.
Since the start of the pandemic, 3,689,746 people have been infected with Covid-19.
A total of 6,853,327 first vaccine doses have meanwhile been administered, the government said, while 472,446 people have received two full doses.
The seven-day rolling average of first doses given in the UK is now 369,536.
Based on the latest figures, an average of 407,334 first doses of vaccine would be needed each day in order to meet the government's target of 15 million first doses by 15 February.
Addressing the UK’s death toll, Mr Hancock said: "My thoughts are with each and every person who has lost a loved one - behind these heart-breaking figures are friends, families and neighbours.
"I know how hard the last year has been, but I also know how strong the British public’s determination is and how much we have all pulled together to get through this."
Sir Keir said: “We must never become numb to these numbers or treat them as just statistics. Every death is a loved one, a friend, a neighbour, a partner or a colleague. It is an empty chair at the dinner table.
“To all those that are mourning, we must promise to learn the lessons of what went wrong and build a more resilient country. That day will come and we will get there together.”
The full toll, as elsewhere, is likely to be even higher, due in part to missed cases early on in the pandemic.
Separate figures published by the UK’s statistics agencies, including the Office for National Statistics, show that there have now been 115,000 deaths involving Covid-19.