The private trauma of Constable Lock, quiet hero of the Iranian embassy siege

Rescued by the SAS in May 1980, the ex-policeman – in his first interview for 10 years – reveals his struggle to Rachel Shields

Thirty years ago, Trevor Lock wrestled a man to the floor and held a gun to his head as he begged for mercy. Today, it is hard to reconcile that Trevor Lock with the softly spoken man gazing out of the window at his well-tended garden. The deep hollows under his bright blue eyes are the only giveaway that he is something more than a contented pensioner; the only hint that he is plagued by memories of chaos, gunfire and bloodshed.

PC Lock, as he was then, was, of course, one of the heroes of the Iranian embassy siege. It is not a mantle that sits easily with him. He has done no book deal; does not pitch up on TV news as a pundit for every hostage situation. This interview is his first for more than a decade.

The man he tackled and held down. thereby saving the life of an SAS man, was the leader of the hostage-takers who threatened to kill them even as SAS troops swarmed into the building. Moments later the man was dead, a line of bullet holes from an SAS machine-gun ripped diagonally across his torso, blood pooling on the floor.

The six-day siege that had gripped the world was over. But not for Mr Lock. "I still think about it every day," he said this weekend at his home in Dagenham, Essex.

Fiercely private, he remains stoic about his ghosts: "It is the classic symptom of post-traumatic stress, isn't it? It never goes. There was no such thing in those days. You related to the physical injuries; the bust nose or ear, but if you had a psychological problem, that was sissy stuff."

A former member of the diplomatic protection squad, Lock was guarding the Iranian embassy in London's leafy South Kensington on 30 April 1980 when he was taken hostage with 25 others by Iranian separatists demanding autonomy for a region in the south of the country and the release of 91 prisoners. Unbeknown to the terrorists, Lock had a handgun strapped to his torso, which he managed to conceal until the final day of the siege, when the SAS entered the building.

"It was part of our reputation at the time, that the British police were not armed," he says. "They'd patted me down, but hadn't found it."

He was awarded the George Medal for bravery for his role in the siege, yet, even now, he is uncomfortable with the label hero – he declined, for example, our request to be photographed – and he harbours regrets. "I'd like to have helped one of the hostages [Abbas Lavasani]. He was like an innocent lamb, offering himself up to the slaughter," he says. "He said if they were going to kill a hostage, he wanted it to be him."

It was the terrorists' murder of Lavasani, a press attaché, on the sixth day of the siege that prompted the then Prime Minister, Margaret Thatcher, to give the SAS the go-ahead.

"They threatened to kill us all. It sounds very melodramatic, but death was in the air. The only thing I can compare it to is animals in an abattoir; all they know is eating and sleeping, but they still know it's bad news."

Though another hostage died when the SAS stormed the embassy, 24 of those held were saved, with TV cameras bringing the SAS to public attention for the first time. TV newsmen watched as the black-clad troops abseiled down from the roof of the embassy before storming the building.

Five of the six militants were killed by the SAS during the rescue mission. The only surviving gunman, Fowzi Nejad, was sentenced to life for his part in the siege. Nejad was freed in 2008, and remains in hiding in Britain.

Coverage of the raid helped to turn Kate Adie into a household name and propelled her to a career on the frontline of world hotspots. The raid was also fodder for a slew of TV programmes, films, books and articles. A new book, Go! Go! Go! The Definitive Inside Story of the Iranian Embassy Siege, was published just last month.

Lock is dismissive: "It is just another book ... just a couple of guys trying to make some money," he says, sipping from a small glass of red wine. Since his retirement in 1992, he has cared for his wife, Doreen, who suffers from severe osteoarthritis.

"I always had the attitude that selling my story would be like selling my soul. Because of the circumstances – I was a police officer – I couldn't really talk about it."

While the father of six relied on the support of family and friends after the siege, some of his colleagues were less understanding. "One guy said to me: 'When you were in there I wasn't jealous of you, but now you're out I am.' He was jealous of all the attention," he says, with a wry smile. "It's not my scene: I'm not an extrovert."

But though he received a lot of attention, he got little in the way of rewards. The couple live on his police pension in a modest semi-detached house in Essex, filled with photos of their six children, 17 grandchildren and four great-grandchildren.

"There were lots of promises made, but they never had any foundation. A promotion. A book – I was going to have a ghost-writer ... but they never happened. When it all happens, you are so happy to still be here that all that is secondary."

He donated his George Medal to the police museum, after storing it in his wife's knitting basket for years.

While the other hostages held in the siege meet up regularly, Lock shies away from these events. "The other hostages have a reunion; it used to be every year. I don't enjoy that stuff. I don't enjoy glorifying it, basically."

He went to one in the 1980s. "We got invited to a barbecue and everyone was there ... from then on I've kept away. I've met the other hostages a few times since it happened, at events, but I've never put myself out to."

Even now, he is unwilling to let himself be defined by the events of three decades ago. His one concession to all the hoopla that surrounds the siege, and will inevitably surface again with the 30th anniversary, is to accept, with good grace, that his family are proud of his heroic actions. "The grandchildren used to come home and say that they'd learnt about me in history," he smiles. "It is history now."