LONDON - As US President Joe Biden last week demanded an explanation of the origins of COVID-19 from the US intelligence community, it has become increasingly evident that only politics can substantiate the virus origins story America likes.

This is agreed by multiple American officials and experts, who believe that conspiracy theories that the virus was leaked from a lab are fundamentally rooted in politics, according to an article carried by the Financial Times on Monday.

Current and former officials said an important factor in the Biden administration's acceptance of the lab leak theories, which Democrats used to refute, is that former US President Donald Trump, who embraced the fabrication, was out of office.

The Democrats therefore no longer need to worry that Trump's efforts to vilify China and deflect blames would help him in election.

Biden said last week that a third of the 18 branches of the intelligence community were more inclined towards the lab-leak theories, for which they do not have enough evidence, according to Financial Times.

"The community as a whole is far away from reaching anything that we could call even a halfway firm conclusion," the article quoted Paul Pillar, a former senior Central Intelligence Agency official, as saying.

"The fact that many of the agencies involved have not reached a consensus even for a 'low confidence' judgment tells you they're a long way away from anything conclusive," he added.

The World Health Organization (WHO) said in March that COVID-19 introduction through a laboratory incident was considered to be an "extremely unlikely" pathway, refuting lab-leak theories.

The lab-leak theories are dismissed by scientists as being false. German biologist Matthias Glaubrecht, scientific director and professor from the Department of Animal Diversity at the University of Hamburg, recently told German media outlet Der Spiegel that the theory is falsely claimed, and some media reports from the United States are based on hearsay.

In an interview with the Australian Broadcasting Corporation last week, University of Sydney Professor Dominic Dwyer, who along with scientists from other countries spent four weeks in Wuhan of China on a COVID-19 origin-tracing mission of the WHO, said there was no evidence to back up lab leak theories.

British Prime Minister Boris Johnson said he was not convinced by lab-leak theories, according to an exclusive CBC interview aired on Sunday.

"I've got an open mind on this, but I'll be clear with you -- so far, the stuff I've seen does not suggest that the ... number one candidate for this is a lab leak," Johnson told CBC News chief political correspondent Rosemary Barton.

"So the stuff I've seen suggests that at the moment, the number one suspect for the origin of this disease is still a zoonotic disease that occurred as a result of the farming of wild animals in some way," he added.