Britain’s spy agencies risk having their intelligence methods revealed if Donald Trump releases a controversial memo about the FBI, congressional figures have warned.

The UK will be less likely to share confidential information if the secret memo about the Russian investigation is made public, according to those opposing its release.

Mr Trump is expected to tell Congress on Friday that he has no objections to the memo being released. He is also not likely to request that any of part of it be redacted, senior sources in the administration have told US media.

A source in US Congress looking into Russian election meddling told The Telegraph that Britain’s security services would be “rankled” if the information is made public.

Figures in America's Justice Department have also reportedly been warning that the UK-US intelligence sharing relationship could be damaged by the move.

British officials were braced for the release of the document on Thursday but played down the impact it would have on how the countries work together.

It comes amid a fierce partisan battle in Congress about releasing the memo, which is written by Republicans and criticises the FBI’s handling of the Russian investigation.

The three-and-a-half page note is based on confidential intelligence and centres on Christopher Steele, the former MI6 agent who wrote a dossier of lurid claims about Mr Trump.

It reportedly criticises how the FBI used information in Mr Steele’s dossier to secure a wire tap on a Trump campaign adviser, Carter Page, before the election.

Republicans want the memo published – critics claim because it will undermine the investigation looking into Trump campaign links to Russia – while Democrats want it kept private.

The row has also pitted Mr Trump, who said this week he “100 per cent” backs the memo’s release, against the FBI, which has expressed “grave concerns” about such a move.

The US president could approve its release as early as Friday after Republicans on the House intelligence committee, who wrote the investigation, voted to publish it on Monday.

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There are fears that releasing the memo could infuriate Britain because Mr Steele is a former MI6 agent and the UK regularly shares information with the Americans.

The congressional source working on a Russian election inquiry told The Telegraph: "British intelligence is likely to be rankled because they view Christopher Steele as one of their own."

The Washington Post reported fears among law enforcement officials that publishing the document could "curtail intelligence-sharing with some of our closest allies, including Britain".

Adam B Schiff, the most senior Democrat on the House intelligence committee, has warned that US spy agencies could see less intelligence being shared if the memo is released.

He wrote in The Washington Post: "Sources of information that the [US intelligence] agencies rely upon may dry up, since they can no longer count on secrecy when the political winds are blowing. This is a grave cost for short-term political gain.”

Britain and America are both part of the Five Eyes, a pact that sees confidential information shared regularly between the two countries as well as Australia, Canada and New Zealand.

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UK security bodies have a history of clashes with the Trump administration. Police reacted with fury when photos and details of last year’s Manchester bombing leaked to US media just days after the attack.

GCHQ also issued a rare public denial when Sean Spicer, then White House press secretary, said it had been involved in wiretapping Mr Trump before the election.

That claim was “utterly ridiculous”, a GCHQ spokesman said. The FBI and the US Justice Department have made a string of last-minute pleas to the White House and congressional leaders for the memo not to be released.

A FBI statement on Wednesday read: “We have grave concerns about material omissions of fact that fundamentally impact the memo’s accuracy.”

Spokespeople for the British Embassy in Washington and the US Justice Department declined to comment.