Idaho Senator Larry E. Craig, a Republican politician who has consistently stood against gay rights, has been found guilty of disorderly conduct in an airport bathroom, court spokespersons have revealed.

Mr Craig, 62, received a $500 (£250) fine and a year’s unsupervised detention but escaped a ten day jail sentence.

His political future hangs in the balance, however, following the publication of a detailed account of his behaviour in Minneapolis-St. Paul International Airport.

A police report obtained by Capitol Hill newspaper Roll Call reveals Mr Craig was arrested in a sting operation intended to tackle illicit sexual activity in the toilets of the airport.

A plainclothes officer, who sat in an adjacent cubicle, describes how Mr Craig repeatedly tapped his foot – supposedly a well-known signal for sex – before brushing his foot against the officer’s and eventually resorting to waving his hand underneath the cubicle partition.

The officer then showed Mr Craig his badge.

Back at the police station, being interviewed about the incident, Mr Craig returned the favour – giving police a business card revealing him as a Senator and saying: “What do you think about that?”

Despite his guilty plea, Mr Craig is professing his innocence in the matter.

“At the time of this incident, I complained to the police that they were misconstruing my actions,” he said.

“I was not involved in any inappropriate conduct.

“I should have had the advice of counsel in resolving this matter,” he continued.

“In hindsight, I should not have pled guilty. I was trying to handle this matter myself quickly and expeditiously.”

Already, the guilty charge has had a devastating political impact on the Republican.

He has quit his role as co-laison to the Senate in the Republican presidential campaign of Mitt Romney and could face a Senate ethics committee review.

The Romney campaign team said: “‘Senator Craig has stepped down from his role with the campaign. He did not want to be a distraction, and we accept his decision.”

Spokespeople for the Senator were putting off questions about whether he would run for re-election, telling journalists it was too early to make any decisions.

But gay activists leapt on the announcement as proof of Mr Craig’s hypocrisy.

Matt Foreman, executive director of the National Gay and Lesbian Task Force, said: “What’s up with elected officials like Senator Craig?

“They stand for so-called ‘family values’ and fight basic protections for gay people while furtively seeking other men for sex.”

He continued: “And by the way, why are Minneapolis tax dollars being used to have plainclothes police officers lurking idly in airport restroom stalls?”

Mr Craig, now in his third term, supported a proposed amendment to the constitution banning same-sex marriage and voted for the Defence of Marriage Act. He opposes the inclusion of gays in the military.

Only last year Mr Craig was batting away accusations by a gay rights activist that he had enjoyed sexual liaisons with other men as “completely ridiculous.”