IT should have been a covert operation in the fight against IRA terrorists in Britain.
But when Detective Sergeant John Woodhouse – the real-life Sweeney – crashed into the back of the car he was tailing, the job instead became a masterclass in impromptu acting.
The mishap has been recounted in 69-year-old John "Woody" Woodhouse's autobiographical A Copper At The Yard.
The book intertwines real-life tales of Scotland Yard with his own mortality, and the battle he faced after being diagnosed with terminal cancer as a young man.
Father-of-three John, who was in the bomb squad from 1969, had already been in the police service for two years when he was assigned to the team to track terrorists suspected of setting off incendiary devices.
John, who lives in Kelvedon Hatch with wife Susan, said: "The car I was tailing in my unmarked police car drove off to a T junction at the top of his road. He drove off, I followed, looking left and right.
"But unfortunately he had paused halfway out to let a car pass. I went into the back of him.
"So I had to give it the whole East End thing: 'What do you think you're doing? You're some kind of nutter'."
"The last thing he wanted was trouble so he drove off fast.
"I got back into the car and I heard on the police radio: 'Woody's just hit him!'
As a police officer, John's career weaved around the streets of east London and China Town, down the corridors of New Scotland Yard and into the offices of the Flying Squad and SO11, the intelligence branch.
After swapping a trowel on a building site for a truncheon on the beat, and then being given a series of promotions, John's career was all going to plan – bar an early episode when, as a PC, he thought he was going to be killed as a huge group of protestors surrounded him and his colleagues, threatening to hurl them through a 12-foot window.
Later there was the first time a dead body spoke to him, and seeing a woman in a red dress now always makes him queasy.
John and the Flying Squad team had been dispatched to Ascot on Ladies' Day to tackle pickpockets in the early 1970s.
But no matter how much they were enjoying the horses, and the spread of sandwiches and wine, nothing could trump the vision in scarlet that walked past in stunning, flowing satin.
"As she walked past everyone just stopped what they were doing and stood agog," he said.
Needing the toilet, John went into the nearest convenience.
Only then the door opened behind him and the lady in red idled up to use the urinal next to his.
He said: "Never in the field of human conflict had the Flying Squad ever backed down. We are not cowards, but there is always an exception.
"Even now I can't see a red dress and hat without the hairs on my arm standing up a little bit."
However, John's life isn't all amusing anecdotes.
At the age of 38, while helping clear the streets of criminals, he was told he had just three months to live after being diagnosed with terminal lung cancer.
But instead of giving up, he phoned a doctor friend who booked him at The Royal London Hospital where he had a lung removed.
He said: "On the evening of the second day in hospital, the doctor said, 'I'm going to operate tomorrow and take the whole left lung out. You've got a 50/50 chance of surviving the cancer'.
"The day before I was going to die and now he's telling me I've got a 50/50 chance.
"Ten days later he said, 'I've got some bad news, I need your bed'.
"You've got to laugh at these situations.
"Nine months after that I went back to yard."
So John, with a renewed sense of life, beat the odds and returned to work, minus a lung.
He said: "No more guns, no more fast cars, so pen and a desk. I was put in charge of looking into the Chinese Triads. We know nothing about it. So we had to set up a criminal index on them."
Reflecting on his brush with cancer, he said: "There is no doubt that I am a very, very lucky guy to survive cancer.
"The last stage of the recovery process is realising not to waste a second of time in pity as life is so precious, and to get out there and live every minute, every hour, every day, or in my case every year, which includes doing all the things you've got to do before you die, from boozing in the bay of San Francisco to dining out on the Hudson River in New York."
But ask any member of Scotland Yard who John Woodhouse is, or indeed "One Lung", as he was nicknamed, fighting crime may not come as high on the list as Morris dancing.
It started as a tease in a pub when John defended Morris dancing in a silly spat with a colleague.
But thanks to this, John and the rest of his team found themselves facing the prospect of performing a Morris dancing skit in front of hundreds of coworkers.
And with help from a real Morris dancer, the performance was applauded as a huge success.
He still performs each year at The Shepherd pub in Kelvedon Hatch, with his trusty truncheon in tow.
Life is still busy for John.
He said: "I just hope when my grandchildren are asked, "did you know your granddads?" they will reply, "Yes, a normal one and a nut case."
He then added: "Thank God I'm not the normal one."
The books is launched on February 16 from 11am at Waterstone's in Brentwood High Street.
