Manchester, London, Northumbria and West Midlands police are visiting the homes of men convicted of consenting same-sex behaviour and demanding they provide DNA samples. The convictions date back three decades and were under the homophobic "gross indecency" law that has since been abolished.

According to reports I have received from the victims, police officers turned up unannounced on their doorsteps. They were handed letters requiring them to give DNA samples to be stored on a police data base alongside the DNA of murders, rapists and child sex abusers.

The men were warned that failure to comply could render them liable to arrest.

This DNA sweep is supposedly part of the government’s crackdown on serious violent and sexual offenders, using powers under the Crime and Security Act 2010. These powers were intended to ensure that everyone who is deemed to pose a threat to the public has their DNA matched against the DNA from unsolved crimes and has it stored on the national DNA database to check against future crimes.

Police have apparently lumped gross indecency - the victimless offence that was used to jail Oscar Wilde in 1895 - with violent sexual assaults and child molestation. This law was only repealed in 2003.

The DNA collection is code-named "Operation Nutmeg". It is sanctioned by the government and the Association of Chief Police Officers. This makes it likely that similar DNA dragnets are happening in other parts of Britain. We don’t know about them yet, because the victims have not alerted anyone.

Men convicted of the now repealed consensual offence of gross indecency are, in effect, being rebranded as serious criminals and treated on a par with vicious, violent sex fiends.

They are being forced to go through the trauma of police abuse all over again.

The letters and threats left one gay man in Northumbria severely traumatised. He was arrested and convicted at the age of 17 for a consenting offence. Now, nearly 30 years later, he’s being forced to relive his past homophobic persecution by the police. He was the victim of bigoted policing in the 1980s. Once again he’s being equated with serious sex criminals who are a menace to the public.

He wants to remain anonymous because he fears repercussions. He told me:

“I am now 45 years old with my own business. I have been in a relationship for over 10 years. Dragging all this up from my past has made me depressed. I now can't sleep or eat since it happened. I feel like stopping it. I am sick of it. I’ve been suicidal.”

He is not the only victim to come forward.

Another man, Stephen Close, who now lives in Salford, was arrested and jailed for "gross indecency" in 1983, when he was 20. He was in the army at the time and was abused by military police and subjected to violent assaults. He eventually confessed to having sex with a fellow squaddie.

Although homosexuality was partly decriminalised for civilians in 1967, it remained an imprisonable military offence until 1994. Close was jailed for six months and discharged from the army with disgrace.

Greater Manchester police claim his offence falls within the list of sex crimes that require DNA samples to be taken.

Close said:

“How long must I endure this burden? Will I ever be able to lead a normal life without worrying whether my past will come back to haunt me?”

The letter to Close from Greater Manchester Police 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; 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 7 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.”

Since these DNA trawls have been exposed, Manchester and Northumbria police have claimed the men were only targeted because they have other convictions, in addition to gross indecency. But it is hard to believe that Close’s conviction for a minor theft, for example, makes him a threat to the public. Moreover, the victim in the West Midlands is adamant that gross indecency is his only conviction.

The Home Office now appears to be suggesting that the three police services have gone too far. A spokesperson said:

“Forces seeking DNA samples from people convicted solely of consensual acts which are no longer criminal is (sic) going against both the intention of the legislation and the ACPO (Association of Chief Police Officers) guidance.”

To resolve the matter, perhaps the Home Secretary and the respective Chief Constables should announce a halt to this homophobic DNA harvesting and write personal letters of apology to the men affected? The DNA samples already collected should be destroyed.

Inadvertent cock-up or homophobic conspiracy? You decide.

Peter Tatchell is Director of the human rights organisation, the Peter Tatchell Foundation