A further 980 people in Britain who had contracted coronavirus lost their lives in the 24 hours before Thursday evening, health officials announced on Friday.
It is the United Kingdom's worst single-day death toll since the outbreak began, and eclipses even the very worst days suffered by either Spain or Italy, the country worst hit by the deadly virus.
And the daily rate of deaths is still expected to rise yet higher for several days to come, said officials.
The country's coronavirus death toll now stands at nearly 9,000 - the fifth-highest in the world.
The UK government has faced a barrage of criticism over its responses to the outbreak, including charges that it delayed a lockdown in a widely reported bid to build "herd immunity", that it lacked widespread testing for the virus, that it failed to join a European Union-wide ventilator procurement programme, and that it failed to provide enough personal protective equipment (PPE) to front-line healthcare staff.
Health Secretary Matt Hancock said on Friday that new testing centers had been opened to allow all front-line healthcare workers to be tested, while a "Herculean" effort was underway to ensure they received PPE.
Prime Minister Boris Johnson - who boasted of shaking hands with people in a hospital where he said coronavirus patients were being treated, just three weeks before the country was forced to shutter non-essential businesses and place movement restrictions on ordinary Britons - was said to be in an "early recovery phase" of his own battle with the virus, having spent much of this week being treated in a London hospital's intensive care unit.
"He must rest up," his father, Stanley Johnson, told BBC radio. "You cannot walk away from this and go straight back to Downing Street and pick up the reins without a period of readjustment."
The prime minister's father, who, as Britain was preparing to go into lockdown last month, said he would defy government advice and continue going to the pub, also said on Friday that Johnson's hospitalization had "served an amazing purpose" in that "it's got the whole country to realize this is a serious event".
The severity of the crisis that has developed over the past few months - and that has seen half a million front-line health workers turning their efforts to fighting the pandemic and the construction of emergency mortuaries in London's parks - was again underscored by Friday's statistics from the Department of Health and Social Care. Of a total of 316,836 tests carried out across the country so far - 19,116 of which were performed on Thursday - there were 73,758 people who had tested positive.
The grim statistics come as the government told Britons to resist going out in the spring sunshine over the Easter weekend.
"However warm the weather, however tempting your local beach or park, we need everyone to stay at home because in hospitals across the country NHS [National Health Service] staff is battling day and night to keep desperately sick people breathing," said health minister Matt Hancock.
Dr. Abdul Mabud Chowdhury, who had urged the prime minister to better supply protective equipment to health workers, died on Wednesday. The 53-year-old urology consultant had worked for the NHS for more than 20 years after migrating from Bangladesh.
He was one of at least six health workers known to have died from coronavirus in the UK. On Friday, as British media reported three nurses who had been pictured on social media wearing plastic refuse sacks in place of official protective clothing had all tested positive for coronavirus, Chief Nursing Officer Ruth May would not be drawn on divulging the number of health workers who had died since the crisis began.