Around 2,350 hospitalised patients who tested positive for coronavirus have died in the UK - marking a daily jump of more than 500 for the first time.
Meanwhile, the number of confirmed cases rose to 29,474, according to government figures.
The Department of Health and Social Care said on Wednesday the official death toll for hospitalised patients stood at 2,352 - an increase of 563 from the day before.
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On Tuesday, it emerged two teenagers had died in the UK after contracting Covid-19, including a 13-year-old boy with no known underlying health problems.
The latest figures show the number of confirmed infections in the UK has risen by around 20,000 in the space of a week.
The total number of positive tests stood at 9,529 on 25 March.
Nearly 153,000 have been tested for the virus to date, according to Wednesday's figures.
The government is coming under increasing pressure over Covid-19 testing as the UK experienced its biggest day-on-day rise in deaths so far.
Around 8,000 test per days are currently being carried out across the UK even though ministers previously claimed a target of 10,000 tests per day had been hit.
At present, the focus is on testing patients in hospital to see if they have coronavirus, with NHS trusts told earlier in the week they should use up to 15 per cent of any spare testing capacity for NHS staff.
Matt Hancock, the UK's health secretary, has now scrapped that cap, telling NHS hospital labs to use all spare capacity to test their frontline workers.
On Wednesday, the prime minister's official spokesman said more than 2,000 NHS staff had now been tested, adding: "We're very clear that we want more testing to be carried out, and that we are working with NHS England, Public Health England and others to ensure that happens."
Additional reporting by Press Association