Image caption Undercover officer Mark Kennedy had relationships when working covertly.

A group of women who claim they were tricked into sexual relationships with undercover policemen have spoken for the first time.

In exclusive interviews with the BBC they say the officers deliberately invaded their private lives in order to spy on them.

A group of eight women are now suing the Metropolitan Police, claiming the deceit has caused them lasting damage.

The Met says such relationships are "never authorised".

Most of the women, who are also suing the Association of Chief Police Officers (Acpo) as well as the Met Police, were environmental campaigners.

They say the deceit has caused them lasting psychological damage, with symptoms including panic attacks, extreme paranoia and post-traumatic stress disorder.

The women came into contact with five undercover officers who carried fake passports and other identity papers and were involved in various undercover operations between 1987 and 2010.

Last year, undercover officer Mark Kennedy was dramatically unmasked by an environmental protest group he had spied on for seven years.

He admitted having relationships with two women during that time.

But three women suing the Met say they had a long-term intimate relationship with him, as he posed as protester "Mark Stone".

'Soul mate'

Lily - not her real name - was in a two-year relationship with "Mark Stone" until 2005.

Media playback is unsupported on your device Media caption 'I feel very betrayed and used': Three women involved in the legal action speak to File on Four

"He was a serving police officer and he never should have touched me whatever the circumstances," she said, speaking to Radio 4's File on 4 programme.

"He was the responsibility of his commanding officers and he was on duty every minute he was with me - he was their responsibility."

Lily says she fell in love with the undercover officer and thought he was her soul mate - but all the time he was informing on her.

"It wasn't just that someone lied to me, it was that there was a whole team of secret people digging away at my life - and personally for me it is very important to know how deeply they were intruding into my private space," she says.

"These shadowy figures were presumably making decisions about my dinner dates and whether or not I was going to spend the night with my boyfriend, reading emails, listening to phone calls - deeply personal stuff."

There are lots of safeguards put in place to ensure officers are not only gathering evidence but it is done ethically and with integrity Patricia Gallan, Metropolitan Police

A police report found that Mark Kennedy had gone beyond the controls set by his superiors, but he has insisted his handlers knew his every move and must have known he was having relationships while working undercover.

The Metropolitan Police strongly disputes the claim, but it is reviewing other undercover operations which go back to the 1980s.

There is nothing in the law regulating the police's surveillance activities to prohibit undercover officers having sexual relationships with those they are spying on.

The Met says such relationships are "never authorised", but also argues it is not possible to legislate for every circumstance.

Deputy assistant commissioner Patricia Gallan told the BBC: "If a circumstance happens where that [a relationship] happens with an officer then I would expect them to immediately report that to a supervisor.

"Each case needs to be looked at on its merits but it is something I would question severely about why it has happened."

"We are very clear with officers that when an operation is authorised there is what is called 'use and conduct' and it is reported back what they are doing [and] what the evidence is they are receiving.

"It is gone through not just a cover officer, but a detective inspector, and that goes up the line and eventually that appears before an authorising officer on a monthly basis.

"There are lots of safeguards put in place to ensure officers are not only gathering evidence, but it is done ethically and with integrity."

The next stage in the legal action takes place in the High Court next month, where the Metropolitan Police will be applying to have some of the cases heard in a secret police tribunal.

If that happens, the women and their lawyers may not be allowed to participate or hear evidence.

Senior police officers are currently working on improvements to undercover policing - but these remain confidential.

The government says the system can be improved and is bringing in new legislation. However, the government has also hinted it is unlikely to make it illegal for undercover officers to sleep with people they are spying on.

Listen to the full report on File on 4 on BBC Radio 4 on Tuesday 2 October at 20:00 BST and Sunday 5 August at 17:00 BST. Listen again via the Radio 4 website or the File on 4 download.