Mark Kennedy says he infiltrated community centre, obtaining intelligence that helped police storm it and close it down

The controversy over the undercover policeman Mark Kennedy has deepened after he admitted spying on and disrupting the work of activists in another European country.

Kennedy has admitted that he infiltrated a Danish community centre that had housed progressive causes for more than a century, obtaining intelligence that helped police to storm it and close it down in violent raids.

He told a Channel Four documentary, to be broadcast on Monday, that he was used by police all over Europe to gather intelligence on activists.

The documentary describes him as the "go-to cop for foreign governments who needed information about their own activists".

Kennedy said he was "under huge pressure to gather all this intelligence and feed it back" after European governments asked for his help.

Details of his deployment in Germany, Iceland, and Ireland have previously been revealed, leading to criticism that British police were interfering in the democratic affairs of other countries.

Kennedy said he went to 22 countries in total during his seven years under cover, pretending to be an environmental activist. The list also includes Spain, Poland, France, and Belgium.

His unmasking has led to the launch of 12 inquiries this year into a network of police spies that has operated in political movements over the past four decades. The inquiries are examining allegations ranging from alleged lying in court to the use of sexual relationships as a way of gathering information about campaigners.

Kennedy transformed himself from an ordinary policeman into a long-haired, tattooed protester who, operating under the fake identity of Mark Stone, spied on environmental, leftwing and anti-fascist groups from 2003.

He become trusted by other campaigners and soon started to become active in European protests. He said he was "getting sent all over the place" after the National Police Order Intelligence Unit, the secretive body he worked for, agreed to loan him out to police forces around Europe.

Police forces have secretive agreements to exchange undercover police officers across their borders.

Kennedy told the documentary-makers that he helped to close down the popular Copenhagen Youth House community centre. Since the late 1890s, the four-storey red brick building had been the base for a variety of trade unions, women's groups, anarchists, anti-capitalist activists and musicians, and was visited by Lenin in 1910.

But it became the focus of huge controversy after the city council sold it to a rightwing Christian group and needed to evict the tenants. More than 650 people were arrested during three nights of clashes in 2007.

Kennedy said: "In Copenhagen, I got into a house full of squatters and gave the intelligence which allowed the police to storm the place."

While undercover, he was hired by German police to infiltrate activists between 2004 and 2009, and reportedly committed two crimes including arson. The cases against him were dropped at the urging of the German authorities, who knew his real identity.

Kennedy – who was paid to tell his story in the Channel 4 documentary – said he had no job after leaving the Metropolitan police, nor the prospect of any work. He said: "How can I expect people ever to trust me again?".

He said his life "is a pretty big negative" as he has left his wife and children and is separated from his girlfriend, who was an environmental activist and who helped to unmask him.

Five of the seven undercover police officers in the protest movement who have been exposed so far have admitted having or have been alleged to have had sexual relationships with activists they were keeping under surveillance, despite claims by senior police officers that this was banned.