Boris Johnson appeared to deny the government hopes to perform 10 million tests a day under his 'moonshot' mass testing plan.
At a televised press conference last week, the Prime Minister last week trumpeted plans to introduce mass daily testing, using new types of test, which are not yet available, but that he hoped would deliver results in 20 minutes.
The PM said it could allow "millions" to be performed every day.
And Government documents revealed by the British Medical Journal showed it was hoped that the technology would add 10 million to the UK's testing capacity.
But challenged today by Labour MP Meg Hillier on who was in charge of delivering the astonishing figure, the Prime Minister appeared to distance himself from it.
He told the Commons Liaison Committee: "I don't recognise the figure that you have just given.
"But what I can tell you is that... there is an opportunity to do something that is wholly separate from the expansion of NHS Test and Trace, and that's to see if we can get to a world in which there is a test and release system, as it were."
The Prime Minister admitted there was not enough coronavirus testing capacity.
He said: "We don't have enough testing capacity now because, in an ideal world, I would like to test absolutely everybody that wants a test immediately."
He promised that there would be capacity for 500,000 tests a day by the end of October.
But he urged people without symptoms to stay away from testing centres - although he acknowledged the reasons why they may want to find out if they had Covid-19.
"What has happened is demand has massively accelerated just in the last couple of weeks," he told MPs.
He added: "Actually, and I know that many people have had infuriating experiences, and I do sympathise with them.
"And we are trying to get as many tests out as we possibly can. But 89% get their results within 24 hours, if you have an in person test."
The Prime Minister promised in June that this figure would be increased to 100% by July. It was not.
He went on: "And the distance that you have to travel to get a test has come down just in the last week. On average from about six or seven miles to about five miles."
This figure only counts people who actually travelled to take tests - and wouldn't account for people who were offered tests tens or hundreds of miles away from their homes and decided not to travel.
The Prime Minister insisted: "We are putting out many, many more tests."
