Police are facing a growing chorus of criticism over visits to the homes of gay men with historic convictions who are being told they must put their DNA on the sex offender's database.
The Crime and Security Act, which became law last year, allows police to secure DNA from ex-offenders to help solve serious crimes such murder, rape and manslaughter.
But officers appear to also be targeting people once convicted with gross indecency – the charge brought against Oscar Wilde in 1895 and only repealed in 2003.
Police demanded DNA from a former member of the armed forces who was convicted of gross indecency for sleeping with one of his colleagues in 1983 and a Northumbrian man who said being reminded of his unjust conviction had made him feel suicidal.
"Police have apparently lumped gross indecency with violent sexual assaults and child molestation," gay rights campaigner Peter Tatchell said.
"Given that this operation is sanctioned by the government and the Association of Chief Police Officers (Acpo), similar witch-hunting and threats may well be happening in other police areas in other parts of Britain.
"Men convicted of the now repealed consensual offence of 'gross indecency' are, in effect, being rebranded a serious criminals and treated on a par with the most vicious, violent sex fiends.
"They are being forced to go through the trauma of police abuse all over again."
Labour demanded that the Home Office takes action to ensure gay men with historic offenses were not being targeted by police.
"The home secretary must make sure that the Acpo guidance on Operation Nutmeg is being properly and rigorously followed by every police force, ensuring that there can be absolutely no question of gay men being unfairly targeted to give DNA samples," shadow home secretary Yvette Cooper said.
"I also urge the home secretary to do more to ensure that gay men who still have offences on their criminal record which have now been decriminalised, know how and where to apply to have those convictions removed."
Tatchell obtained a copy of the greater Manchester police letter to one man targeted by the operation. It states: "Through investigation of police records you have been identified as a person who has a previous conviction, which falls into one of the above categories (Gross Indecency 1983); and from whom we now wish to obtain a DNA sample....
"The sample once taken will be processed and place on the National DNA Database, where it will be retained and may be subject to speculative searching either immediately or in the future.
"You will be asked to consent to provide a sample. If you do not consent at this stage I require you to attend a police station within seven days. The time and date of your attendance can be discussed with the person delivering this letter.
"At the police station the sample may be taken with the authority of a police officer of the appropriate rank. If you fail to attend the police station as required you may be liable to arrest."