The government is “throwing everything” at developing a coronavirus vaccine, Health Secretary Matt Hancock has said.
He told the daily Downing Street briefing that human trials for a vaccine, developed by the University of Oxford, would begin on Thursday.
He also addressed the shortage of protective gear for the NHS, saying the government was talking to thousands of suppliers, but not all could deliver.
Labour said there was a “gap” between government words and reality.
Meanwhile the UK has recorded another 823 coronavirus hospital deaths – taking the total number to 17,337.
Official figures show deaths hit a 20-year-high in England and Wales in the week up to 10 April – nearly double what would have been expected – driven by 6,200 fatalities attributed to coronavirus.
These figures cover all settings, including care homes and deaths in the community as well as hospitals.
Mr Hancock told the No 10 briefing that “the best way to defeat coronavirus” was through a vaccine.
The process was “trial and error”, he said, but the UK was at the “front of the global effort” and had invested more money than any other country.
He said two leading vaccine developments at UK universities – Imperial College London and the University of Oxford – would receive a total of £42.5m to support their clinical trials.
“Both of these promising projects are making rapid progress and I’ve told the scientists leading them we will do everything in our power to support.”
He added: “After all, the upside of being the first country in the world to develop a successful vaccine is so huge that I am throwing everything at it.”
Mr Hancock also defended the government amid mounting criticism over the ongoing shortages of personal protective equipment (PPE) for front-line workers.
He said the operation to get PPE to the front line was “unprecedented”, describing it as “the biggest cross-government operation I’ve ever seen”.
The government was “investigating each lead” from UK-based companies offering help, he said, but the “reality is not each of them who approach us can deliver on scale”.
There had been more than 8,000 offers of help from UK companies and the government was now working with 159 UK manufacturers, he added.
He also said the UK was in “direct talks” with companies abroad to buy items, especially in China.
Meanwhile, an RAF plane is expected to bring a shipment of PPE from Turkey to the UK later.
Some British companies have told the BBC that their offers to help have gone ignored.
One Nottinghamshire-based businessman said he wanted to provide a million face visors as well as gowns – but after an initial response from the crown purchasing team on Friday, heard nothing more.
Jim Griffin, the head of automotive parts firm Interflex said he is now planning to export his protective clothing to other countries.
Labour leader Keir Starmer said there was a gap between the government’s words and reality, in relation to the delivery of PPE.
He told the BBC: “It would be a struggle for any government to get exactly the right kit to the right place at the right time. But what we’re seeing here is an increasing gap between what the government says or thinks is happening and what the frontline are telling us.
“This gap has to be closed as soon as possible because people are putting their lives literally on the line when they’re going to work – they need the proper equipment in the right place.”