Claims an undercover officer set fire to a high street department store while infiltrating animal rights campaigners are being investigated by the police.
The Metropolitan Police announced on Wednesday it was reopening its investigation into the planting of an incendiary device in Debenhams in Harrow in July, 1987, causing £340,000 damage.
The renewed investigation will pursue a number of lines of enquiry, including potential advances in DNA technique, new information and claims made in Parliament by Green MP Caroline Lucas.
In 2012, Ms Lucas used parliamentary privilege to name Mr Lambert as the undercover officer who had pretended to be a radical protester for five years.
She referred to allegations Mr Lambert had been part of a plot with two animal rights activists to set fire to three branches of Debenhams in protest against the sale of fur.
Andrew Clarke and Geoff Sheppard, who were jailed for planting devices at the Romford and Luton stores, launched appeals against their convictions in 2014, on the grounds an undercover officer had been involved in their case.
Mr Lambert denies planting the incendiary device.
A public inquiry into undercover policing in England and Wales is now under way, chaired by Lord Justice Pitchford. It was announced by Home Secretary Theresa May in 2015 after a series of claims about the secretive Special Demonstration Squad.
While under cover in the 1980s, Mr Lambert fathered a child with an activist then abandoned her when his mission ended. The woman, identified only as Jacqui, required psychiatric treatment and considered suicide after discovering the identity of her child's father.
Officers from the SDS used the identities of dead children as cover, and several had relationships with women who did not know their true identity, even fathering children.
So far Scotland Yard has made payouts to eight women who unwittingly became involved in relationships with the officers.
Additional reporting by PA
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