UK Health Secretary Matt Hancock said yesterday he does not know whether the coronavirus vaccine under development at Oxford University will work - but at the same time is determined to give the drug trial his support.
Mr Hancock was speaking on yesterday morning's Andrew Marr Show.
Asked about the collapse of the UK's contact tracing app project - which cannot work on Apple's iPhones - Mr Hancock said things had to be done at speed, and accepted that some projects would not work out.
"We're running at things before we know whether they will come off," he said.
"The vaccine is a case in point.
"I don't know whether the Oxford vaccine will work. Nor does anyone.
"But I'm sure as hell going to give them every support I can to get it to work."
Mr Hancock said England is "clearly on track" to further ease the coronavirus lockdown, with the hope pubs, restaurants and hairdressers in England could reopen as early as July 4.
He said the next steps would be set out this week.
Ministers believe cases of coronavirus are sufficiently low that more reopening can take place to revive the economy.
Also on the Andrew Marr Show, Mr Hancock revealed the government will announce the results of a review into the two-metre rule in England, and the next step for the lockdown, this week.
"I think we are about to see another step in the plan and this week we will announce further details of the measures that we can take to relieve some of the national lockdown measures at the start of July including on July 4," he told the programme.
He gave perspex screens, masks and altered seating arrangements as examples of measures to mitigate the risk of spreading coronavirus if the two-metre rule is changed.
To aid the recovery, Mr Hancock did not rule out suggestions that Rishi Sunak could slash VAT to encourage spending, saying: "It's very much a matter for the Chancellor."
The Health Secretary also said a reduction in the distance rule would "undoubtedly help with schools", and pointed to the example of Northern Ireland where it will be reduced to one metre between pupils.
Later Prime Minister Boris Johnson said he would be "sticking like glue" to his road map for easing the coronavirus lockdown for the hospitality sector from July 4, and confirmed he will this week unveil his plan for the future of the two-metre rule.
In a Downing Street interview, he said: "The disease is increasingly under control and I just want people to reflect on that important fact.
"So, of course, as we make that progress it will be possible to open up more and you will be hearing more about what we want to do with not just non-essential retail but with the hospitality sector from July 4 and we're sticking absolutely like glue to the road map, to the plan that I set out on May 10."