When Lynda La Plante suggested that the groundbreaking Jane Tennison should be gay, she got a polite “no” from its inspiration. It was 1991 and former DCI Jackie Malton felt the television world “wasn’t quite ready”.

Instead, Jackie, who the character is based on, wanted the Prime Suspect series to focus on everything else she had experienced – a female leading the way in a male-dominated environment and for the storytelling to be as realistic and raw as possible.

Jackie spent hours with writer La Plante at her home, going over details of who Tennison was and how she operated. They went through police procedure, language, and forensics, with La Plante monitoring how Jackie moved, dressed, smoked and spoke.

Together they created one of the most iconic TV characters of the past 30 years and set the bar for small screen police drama.

“When Lynda said perhaps we should make her gay, I said no,” says Jackie.

“It was 1991 and I thought the audience wouldn’t be ready for it – it would distract from the story.”

That story went on to be a massive success, with 14 million viewers in the UK, selling to 78 countries, a global audience of 200 million and a major career moment for Helen Mirren.

It was a massive moment in Jackie’s life too, who at the time was one of just three female DCIs in the Metropolitan Police.

In her new book – The Real Prime Suspect – Jackie, who is gay, reveals how she fought against sexism and homophobia to carve out a hugely successful career.

It is an incredible memoir of one woman’s determination to be an officer in a time when policing was more like The Sweeney or Life On Mars. In 1970, aged 19, Jackie joined Leicestershire Police, where women were given a whistle, handcuffs and a handbag.

“You couldn’t get anything into it, mind,” says Jackie.

“The men got a baton instead of a handbag.”

She quickly rose through the ranks and in 1973, at just 22, she became a sergeant joining CID. One of the rituals for women was to have their pants pulled down and a CID ink stamp on their buttocks.

“It was a very common occurrence getting your backside stamped,” says Jackie.

“They did it to me twice, it was humiliating. They didn’t do it to the men, just the women.

“It was all a big laugh to them. But I thought, ‘Go with the flow’, what could you do, to be honest.”

With grit and determination, she became an acting inspector and then in 1979 the call came to move to the Metropolitan Police, where she worked on some of the biggest cases of her career.

She worked across the Brixton riots and the New Cross fire in 1981, where 13 people died; the Harrods bombing in December 1983 which killed three police officers, three civilians and injured 90 people, and the death of PC Yvonne Fletcher outside the Libyan Embassy in 1984.

Working 13 hour days, seven days a week was the norm for Jackie. “I worked around the clock for years. I wasn’t very good at switching off in my head.”

In 1984 she joined the Flying Squad, where women were a rarity. Jackie was given the nickname “the tart” by a male colleague.

“He was just a bully,” says Jackie. “When we were introduced he said **** off, you ****.

I’m not working with a woman.

“I just said, ‘Pleased to meet you!’ Can you imagine that today?

“But that’s just how it was. From what I know now, I think he was full of fear himself. But I got him back in the end.”

He became the toxic character DS Bill Otley in Prime Suspect, played by Tom Bell.

She also had sex toys given to her. But she recalls, “one of the guys got a dead sheep with a knife in the back – so I was quite grateful for my [present], to be honest”.

The constant sniping took its toll, admits Jackie, and drinking to be “one of the boys” became her crux. “There was definitely a sense of loneliness, isolation.

“In a male-dominated profession you go with it or you don’t.

“No-one has an ambition to be an alcoholic. I just went with the flow of drinking with them and I guess it suited me to numb a bit.”

She had relationships in the police but work often took over.

When she was 30 she finally came out to her parents.

“It was an agonising decision,” says Jackie, now 71.

“My father cried for three days, they blamed themselves. It was a different generation – there was absolute shame around it.”

It was even on Jackie’s mind in 1984 when she was asked to be a bodyguard to toddler Prince William. “I just had all these thoughts flooding into my head, ‘Oh I’m gay, what happens if the press find out and then you embarrass the Royal family? And do I really want to be stuck in a nursery school for eight hours a day?'” She declined the offer.

In 1984 she also had her first taste of TV life, when she was asked to advise on The Bill.

Fast forward seven years and she was in La Plante’s home having dinner with Helen Mirren.

Mirren, she feels, was the perfect choice for Tennison. “She was brilliant. She’s cool. I’ve met

Helen loads of times. We’ve had dinner on our own and I spoke to her on set. She brings her own magic to it.”

Before Prime Suspect – Jackiewatched Juliet Bravo, The Gentle Touch and her favourite show was Cagney And Lacey.

“When Prime Suspect won the Bafta in 1992, Sharon Gless came on,” says Jackie. “When they were announcing the winner, we were up against GBH [the series written by Alan Bleasdale starring Robert Lindsay] and I said to Lynda, ‘You’ve won it. It’s Sharon Gless, it’s Cagney, they are not going to give it to GBH!'” In 1992 Jackie stopped drinking and hasn’t touched a drop since.

She left the Met in 1997 and went to work on The Bill until it ended in 2010.

“I was there 13 years, they were really happy times. It was a phenomenal programme to work on, a can-do mentality.” She also advised on Cracker, A Touch Of Frost, Life On Mars and worked again with La Plante on Trial And Retribution.

Jackie, who lives near Guildford, Surrey, feels there needs to be a return to beat policing: “It’s a big bugbear of mine that the police, in my opinion, have lost contact with the public.

“It’s not their fault – they’ve lost police stations, intelligence hubs.

“We knew who our burglars were, who our robbers were.

“I used to have cups of tea with sex workers on the beat and in chatting they would reveal loads of stuff inadvertently.

“It is all about intelligence, communication. It’s about standing in their shoes for a while, trying to understand.”

She worked with the former Metropolitan Police. Commissioner Cressida Dick during her career.

“I’ve known Cressida for 40 years,” says Jackie. “She’s a really, really good person and I wish the public would see that.

“It’s a very tough job for one person to do when you are stuck in the middle of a political battle.”

Jackie. “I had wories that bureaucracy is affecting day-to-day policing too. “It seems to me that a lot of the officers are tied up with mental health issues and spend hours and hours sitting with people, and that is not their job.

“Police chiefs and police and crime commissioners, in my opinion, should be fighting back.

“Thirty one per cent of police officers have less than five years service. Police officers are not looking at it as a career anymore.

“Society is changing, but crime doesn’t.”

In 2009 Jackie took an MSC in addiction psychology and counselling and now volunteers in a prison helping men with addiction issues. As well as her book, she has worked on documentaries and is still looking into the case of eight-year-old Vishal Mehrotra, an unsolved murder back from her days in the force.

He disappeared on the day of Prince Charles and Lady Diana’s wedding in 1981 and it’s a case which has stayed with Jackie.

“When I joined the police they said, ‘We are not interested in the whys and wherefores Jackie’, we are interested in ‘Did you do it or didn’t you?’ I thought life isn’t quite as simple as that. That’s what I loved about being in the police, the delving, asking the questions, not just dealing with people in a black and white situation.

“My job was to do the best I possibly could for the victim and the perpetrator – and to ask those deeper questions.”

Why are we all so interested in crime? “Because we all have a shadow side but we don’t necessarily act out on it. We can sit comfortably in our chairs watching it and be intrigued by it all.

“More women are interested, I think because they are interested in the human psyche.

“Academic papers have been written about Prime Suspect.”

So could we see Tennison back working on a cold case? La Plante hinted at a return last year on the 30th anniversary. “I think there is always an appetite for Tennison,” says Jackie. “She was this iconic character many people of a certain age/era have never forgotten.”