Both the FBI and US Department of Energy have said they believe a lab leak is the most likely cause of Covid, while other agencies have said they think it occurred naturally.

Joe Biden, the US president, has said he does not know where the virus started, while the US National Intelligence Council said last year it “probably emerged and infected humans through an initial small-scale exposure”.

UK ministers are now facing calls to expand the terms of the Covid Inquiry to include an investigation into the origin of the virus.

The Telegraph understands that the call in Jan 2021 was deliberately held on an “open line” without security encryption in the hope that Chinese intelligence agencies would hear that Western countries were aware of military activity in Wuhan.

“We did that deliberately…we wanted to put pressure on the bad guys,” said a State Department source.

Ten days after the call, in which officials said the UK was unwilling to assist with a US-led lab leak investigation or share its own research, the summary compiled by Mr Pompeo’s officials was released to the public in a “fact sheet”.

Those involved in the release said they took care to avoid revealing the sources or methods of US spy agencies, and that it was just the “tip of the iceberg” of the underlying intelligence that had been gathered.

A UK government spokesman said: “There are still questions that need to be answered about the origin and spread of Covid-19, not least so we can ensure we are better prepared for future pandemics. 

“The UK continues to support the World Health Organisation in its expert study of the origins of Covid-19. It is important that China and other countries cooperate fully with the researchers.”