McLibel leaflet 'co-written by undercover police officer'
An undercover police officer posing as an environmental activist co-wrote the leaflet at the centre of the McLibel court case, the Guardian has reported.
A book by two Guardian journalists claims one of the authors of the so-called McLibel leaflet was former police officer Bob Lambert.
The libel case brought against two activists led to the longest running civil trial in English history.
Mr Lambert has yet to comment. The Met said investigations were ongoing.
The book about the undercover policing of protest by Paul Lewis and Rob Evans, to be published on Monday, claims Mr Lambert co-wrote the six-page leaflet in 1986, while posing under the alias Bob Robinson.
Following its publication, McDonald's famously sued two green campaigners, Helen Steel and David Morris, leading to a three-year High Court case that cost the company millions.
'He was laughing'
As part of the now-disbanded Metropolitan Police special demonstration squad, Mr Lambert is said to have spent five years infiltrating the London Greenpeace group involved in the anti-McDonald's campaign.
One former member of the group told the BBC's home affairs correspondent Tom Symonds he remembered Mr Lambert's involvement.
The source said: "There were meetings every week. Anyone could come and get involved. It was a lively kind of open group. It was a loose group.
"There was a handful of people, four or five that went off and wrote what became the fact sheets and Bob was one of those. I know that for a fact."
A woman who says she was in a serious relationship with Mr Lambert at the time the leaflet was written told the BBC she remembered an odd conversation about McDonald's as the couple sat in a park.
Belinda Harvey said: "We were talking about the McDonald's thing and he told me that he co-wrote the leaflet and nobody knew that. And for some reason he thought it was really funny.
"I remember thinking 'Why's that really funny?' and I couldn't understand why he was laughing about it.
"I know why he was laughing about it now."
She says she didn't see him write the leaflet but "he had piles of them in his flat".
The allegations follow a number of recent claims that undercover police working for the special demonstration squad assumed the identities of dead children and that some officers had inappropriate sexual relationships.
Mr Morris - one of those sued by McDonald's - told the BBC: "I think it's disgusting that the police should have had any interest at all, let alone infiltrating and doing the kind of disgusting things that have been revealed in recent months."
The home secretary has appointed Derbyshire's chief constable Mick Creedon to lead an investigation into undercover policing, known as Operation Herne.
Scotland Yard would not comment on the allegations but told the BBC's Tom Symonds: "At some point it will fall upon this generation of police leaders to account for the activities of our predecessors.
"But for the moment we must focus on getting to the truth."