Theresa May reportedly gave up on the idea because she had doubts over whether the US would provide the support needed and whether the hostile parliament would approve such a move.

The UK and France had discussed replacing American forces in Syria with an equal number of troops after Donald Trump’s surprise pull-out announcement last December, The Telegraph reports.

A UK defence official familiar with the matter told the newspaper that the move was supposed to be a “like-for-like replacement”.

Last December, Donald Trump declared that Daesh* had been defeated, and the US would recall its nearly 2,000-person military presence in Syria. Thousands of terrorists are still holding out, and the withdrawal has been going down slowly so far, with 1,000 troops remaining in the country to help 'secure' its oil, as Trump put it.

Both the UK and France have been taking part in the US-led coalition in Syria, mostly in the form of air strikes. Their governments do not disclose the number of troops operating there.

It is understood that both countries were discussing plans to deploy up to 1,000 military personnel on the ground each, driven by concerns that the US pull-out would contribute to a jihadi resurgence.

The British part of proposal was to send fighters from the Special Air Service (a special forces unit), as well as elite forces like the Parachute Regiment and Royal Marines, according to the report.

Theresa May is said to have dropped the plans after a “few days” of intense discussions because she wasn’t sure whether the US would provide the required air cover and logistical support and because there was a sizeable chance that MPs would reject the move.

At the time, Theresa May’s minority government was under massive pressure from the opposition over the prime minister’s Brexit proposals, and eventually suffered a series of defeats when trying to get a withdrawal agreement with the EU through parliament.

Replying to a request for comment, a government spokesman told the Telegraph that the UK “has always taken the necessary steps to secure Daesh’s lasting defeat and we continue to do all we can to keep our country safe.”

May’s successor, Boris Johnson, isn’t thought to have seriously considered the plans to swoop in to replace Americans in Syria.

The US-based journal Foreign Policy quoted an American official in July as saying that the UK and France had agreed to deploy 10 to 15 percent more elite soldiers to Syria. The exact numbers of troops involved were not disclosed.