Evidence that a lab leak in Wuhan sparked the coronavirus pandemic has probably been destroyed by China, the former head of MI6 has said.

Sir Richard Dearlove, who headed up the secret intelligence service between 1999 and 2004, warned that it would be difficult to prove that the Wuhan Institute of Virology was working on ‘gain of function’ experiments to make a natural coronavirus more deadly to humans.

Speaking to Allison Pearson on the Telegraph’s Planet Normal podcast, which you can listen to on the audio player above, he warned that the West had been naive in its trust of China, which had infiltrated scientific institutions and journals in Britain and beyond.

Sir Richard said it was possible that scientists who wanted to speak out about the experiments had been ‘silenced.’

“The People’s Republic of China is a pretty terrifying regime and does some things we consider unacceptable, and extreme in silencing opposition to the official line of the government,” he said.

“We don’t know that’s what’s happened, but a lot of data has probably been destroyed or made to disappear so it’s going to be difficult to prove definitely the case for a gain-of-function chimera being the cause of the pandemic.

“This is why scientific analysis is now so important because although that can’t prove the case 100 per cent, the thorough biochemical analysis puts the weight of evidence to this being a man-made lab experiment, a natural virus that has been enhanced.”

Last week, US President Joe Biden ordered American intelligence officials to “redouble” their efforts to identify the origins of the Covid-19, and report back within 90 days. British intelligence officials are also helping the US in establishing whether the pandemic was caused by a lab leak and several eminent scientists have now called for a major inquiry including researchers who worked on experiments with Wuhan scientists.

Sir Richard added: “The whole argument has shifted and I’m pretty sure in my own mind that the US must have material which has accelerated this development.

“China was originally let off the hook. I think the problem was the style of the Trump regime, a lot of people understandably found it hard to go along with his more outlandish allegations.

“In the end it’s going to boil down to scientific evidence because the data is no longer available, unless some courageous Chinese individual, probably a scientist, comes forward.

“We have been through a period of extraordinary nativete in our relationship with China. 

“Some of the things that were said by George Osborne and David Cameron about our relationship with China, how we were going to have this privileged position, I was staggered at the time by the sheer naivete that they could develop a relationship with China without understanding they were dealing with a communist dictatorship, and one that has its own strategic agenda.

“This is a really important issue and has massive, far-reaching implications. If the outcome is likely to be that serious, which personally I think it will be, I can’t see China agreeing to pay reparations, and I’m not sure what our future relationship with China is going to be.”

Sir Richard said an inquiry into whether the virus leaked from a lab should not be left to the World Health Organisation (WHO) which has been criticised for failing to look rigorously into the issue.

“The WHO looks like a lost cause and that should not be the agency to deliver material which gives us a clear understanding of what the hell happened,” he added.

“The WHO report was farcical and it’s clear now they are losing control of the narrative.”

Telegraph subscribers can listen to an extended version of Allison Pearson’s conversation with Sir Richard Dearlove using the audio player below

Planet Normal – Full interview with Sir Richard Dearlove

Join Allison Pearson and Liam Halligan to discuss China, Covid-19 and the latest Planet Normal episode in the comments section of this article at 11am on Thursday June 3.