Caroline Lucas, the Green Party MP, has alleged in a debate in Westminster Hall that Bob Lambert, a former undercover police officer, placed an incendiary device in Harrow Debenhams in 1987 in order to ingratiate himself with a cell of the Animal Liberation Front. He would later provide intelligence leading to the arrest and conviction of two members of that cell, Jeff Shepherd and Andrew Clark.

Lucas told the Hall:

[Bob Lambert] pretended to be a committed environmental and animal rights campaigner between 1984 and 1988. By the summer of 1987, he successfully infiltrated the animal liberation front, also known as the ALF, a group that operated through a tighly organised underground network of small cells of activists, making it difficult to penetrate.

In October 2011, after he was exposed as an undercover officer, Bob Lambert admitted that, and I quote, "in the 1980s I was deployed as an undercover Met Special Branch officer, to indentify and prosecute members of Animal Liberation Front, who were then engaged in incendiary device and explosive device campaigns against targets in the vivisection, meat and fur trades." Lambert has also admitted that part of his mission was to identify and prosecute specific ALF activists.

He says, and again I quote, "I succeeded in my task, and that success included the arrest and imprisonment of Geoff Shepherd and Andrew Clarke." The men he refers to were ALF activists found guilty of planting incendiary devices in Debenhams stores.

Allegations about what kind of role exactly Lambert might have played in their conviction have only recently come to light. In July 1987, three branches of Debenhams, in Luton, Romford and Harrow, were targeted by the ALF in co-ordinated, simultaeous incendiary attacks because the shops were selling fur products. Shepherd and Clarke were tried and found guilty, but the culprit who planted the incendiary device in the Harrow store was never caught. Bob Lambert's exposure as an undercover police officer has prompted Geoff Shepherd to speak out about that Harrow attack. Shepherd alledges that Lambert was the one who planted it, and was involved in the ALF's co-ordinated campaign.

Shepherd has made a statement, which I have seen, and he says, and I quote, "Obviously I was not there when he targeted that store, because we all headed off in our seperate directions. But I was lying in bed that night, and the news came over the World Service that three Debenhams stores had had arson attacks on them, and that included the Harrow store as well. So obviously I straight away knew that Bob had carried out his part of the plan.There's absolutely no doubt in my mind whatsoever that Bob Lambert placed the incendiary device in the Debenhams store in Harrow. I specifically remember him giving an explanation to me about how he had been able to place one of the devices in that store but how he had not been able to place the second device."

Now, also in that interview, Shepherd says that two months after the three Debenhams stores were set on fire, he and another person were in his flat making four more firebombs when they were raided by police. Shepherd alledges that the intelligence for the raid was so precise that it is now obvious that, I quote, "it came from Bob Lambert", who knew that the pair were going to be there making another set of incendiary devices. Shepherd was jailed for four years four months, and Clarke for more than three years.

Now for Lambert, it was a case of "job done". In fact, so well had he manipulated the situation that he visited Shepherd in prison to give him support before disappearing abroad. Until recently, Shepherd had had no reason whatsoever to suspect that the man he knew as Bob Robinson, assuming that he'd got away with it, fled the country and built a new life for himself.

So it seemed that planting this third incendiary device was perhaps a move designed to bolster Lambert's credibility and reinforce the impression of a genuine and dedicated activist. He did go on, successfully, to gain the precise intelligence that led to the arrest of Shepherd and Clarke, and without anybody suspecting that the tipoff came from him.

But is that really the way that we want our police officers to behave?