In recent months gay people have complained of parks police in London using vans with searchlights and loud speakers, dogs, and plain-clothed officers, as part of a crackdown on gays who use open spaces to pick up partners or have sexual intercourse.
The dispute threatens to harm the improved relations between the gay community and the Metropolitan Police, who are expressing concern at the situation.
Parks police have the power to make arrests, take fingerprints, tape interviews and process paperwork.
Plain-clothed parks police employed by Wandsworth council, the Tory flagship borough in south London, have been patrolling gay pickup areas of Battersea Park since July and have arrested one man. Homosexuals claim that the council is using young male officers as a form of entrapment - a suggestion denied by the council.
A council spokesman said that the patrols were set up following a complaint from a member of the public.
In Hyde Park, central London, there have been complaints of police using vans with loudspeakers and spotlights at night to patrol gay cruising areas. Members of the Royal Parks police, who are funded by the Department of Heritage, have also been accused of hunting in undergrowth with torches for gay men.
A spokesman for the police confirmed that routine patrols were being carried out, but said: 'There's no vendetta against any part of the community.'
Rangers, who are sworn in as special constables by the Corporation of London to patrol Hampstead Heath in north London with dogs, have been accused of deliberately threatening gay men in a well-known pickup zone.
On one occasion in July officers allegedly used their dogs on Peter Tatchell, a gay rights' activist in the group Outrage, who claims he was arrested and dragged off the heath. He is currently taking legal action.
A spokeswoman for the Corporation of London said staff were responding to a report that a man was being attacked. When the rangers arrived they were allegedly confronted by a hostile group. Mr Tatchell was then 'escorted' off the heath.
Jeremy Clarke, director of Galop, the gay and London policing group, called for a special police authority to be set up to monitor the work of the parks police.
Chief Inspector Roger Kember, the gay and lesbian liasion officer at the Metropolitan Police, expressed concern about the action by the parks police. He said: 'It is a worry because we have made progress with the (gay) community. People have complained to us about things we are not responsible for. We have to point out it was not someone from our force - they are from a completely different organisation.'
He said the police usually only take action against homosexuals when there is a complaint.