The three officers, John Walsh, Jonathan Lehrle and Nicholas Jones, all based at Chelsea in west London, were sentenced to two years' imprisonment earlier this month after what they claimed was a jury's 'perverse verdict'. This Thursday, their lawyers will seek leave to appeal to have the verdicts overturned; they will also apply for bail.
The campaign has won the backing of the Labour MP for Thurrock, Andrew MacKinlay, who is Walsh's constituency MP. Mr MacKinlay said: 'I have examined this case closely and I believe the convictions may be unsafe. I am concerned that because of recent miscarriages of justice, which have caused justified disquiet about the conduct of the police, the balance may have swung too far in the opposite direction.'
John Bowis, the junior health minister, who is Jones's MP, is also backing the campaign.
The officers are being supported by colleagues, their former senior officer at Chelsea police station and the Metropolitan Police Federation, whose chairman, Mike Bennett, originally issued a statement saying he had 'no sympathy whatsoever' with them.
Mr Bennett now says he has changed his mind after looking at the details of the case. 'It may be a miscarriage of justice. It raises very serious questions as to whether police officers can get a fair trial.'
At their Old Bailey trial, the Crown claimed the three were noisy after leaving a public house in Chelsea and stormed into the home of Francis Milburn, who had asked them to keep quiet, attacking him and his parents.
The court was told that Mr Milburn was a Sandhurst cadet studying for his final exams. Dressed in his boxer shorts and waving a long United States police truncheon, he leant out of an upstairs window and asked the officers to be quiet.
Mr Milburn claimed they made indecent gestures, told him to come down and then barged into the house and assaulted his parents. During the struggle, Mr Milburn admitted hitting Jones, who was off work for six weeks, but said he believed them to be hostile intruders.
Mr Milburn was cleared by magistrates of common assault. The officers all gave evidence, saying he had hit Jones outside the house and the fracas occurred because they were trying to arrest him.
At their trial, the officers repeated their story; Walsh was cleared of assaulting Mr Milburn's parents.
Mike Walsh, brother of John Walsh, who is organising the campaign, said the policemen and their lawyers were 'amazed' at the verdict, because the prosecution had no evidence to suggest conspiracy to pervert the course of justice.
It was a fact, he said, that the officers had given their accounts of the incident separately afterwards.
'This implies that any officers whose accounts are disbelieved by a court could face prosecution for conspiring to pervert the course of justice, even if there is no direct evidence that they did.'