The House of Commons speaker John Bercow has controversially warned MPs they are banned from revealing the identity of a “celebrity couple” who have taken out an injunction suppressing details of alleged infidelity.

Mr Bercow acted after an unnamed MP said he was planning to use Parliamentary privilege to reveal the details of the couple – whose identities have widely available on the internet and have been published in a Scottish newspaper.

But a court injunction prevents their names being revealed in England and Wales. One way around this would be for an MP to use Parliamentary privilege to reveal the celebrities' identity. This could then be reported by English news outlets without breaking the terms of the injunction.

A similar ruse was used five years ago by the Liberal Democrat MP John Hemming, who identified Ryan Giggs in the Commons when the footballer won an injunction to prevent reporting of an alleged affair.

But now the Speaker has stepped in to stop that happening again over fears that it is an abuse of the Parliament’s historic rights of being an institution ‘above the law’.

A spokesman for Mr Bercow’s Office said this morning he was taking emergency advice from officials with the aim of preventing the couple's names from being revealed.

"Members should not breach the terms of any injunction/super injunction,” he said.

“With respect to how this is to be enforced, Mr Speaker will be taking advice from senior procedural officials later this morning."

A court order bans newspapers in England and Wales from publishing the names of the “well-known” married celebrity who had an extra-marital ménage à trois.

A number of MPs are said to be unhappy with the impact of the injunction on free speech. One politician said he was considering the move because of concerns free speech was being inhibited by “judge-made law”.

A Scottish newspaper yesterday published the couple's names, after their identities were first revealed in an American publication.

However at the moment even the name of the Scottish newspaper cannot be identified in English-based publications because it risks breaching the terms of the injunction.

The celebrity, identified only as ‘PJS’, claimed his right to privacy outweighed an English tabloid newspaper’s right to publish a story about his extra-marital sexual exploits.