The tragic wife of notorious gangster Reggie Kray who took her own life after walking out on him had electric shock treatment in Hackney Hospital which helped erase memories of their doomed marriage, a book out on Thursday reveals in the run-up to next week’s Legend movie about the Krays.

Frances Kray’s marriage to Reggie—who ruled an “empire of extortion and terror” with psychotic twin Ronnie in the 1960s from their mum Violet’s house in Bethnal Green—lasted just two months, according to former journalist-turned-author Jacky Hyams.

The climax of the book is based on an exclusive interview in the local press in 2000—the only time Frances’ brother Frankie Shea, Reggie Kray’s driver, ever talked to the media about her suicide in 1967.

Frances had been portrayed over the years as a simpering, scared, nervous “arm candy trophy wife”.

But Jacky insists she was the opposite, a “bright, bubbly intelligent girl” whose life turned bad when she married into the Kray clan.

The Kray twins were finally brought down in a sensational trial at the Old Bailey in 1969 after Ronnie shot dead rival south London gangster George Cornell in Whitechapel’s Blind Beggar pub and Reggie stabbed petty criminal Jack ‘The Hat’ McVittie to death at the house of ‘Blonde Carole’ in Evering Road, Stoke Newington.

Frances was 14 and still at school at Dalston County High when she met Reggie, according to the Krays’ cousin Rita Smith, now 79, still living in Bethnal Green today.

Reggie had to wait till Fran left school before they could date. But he had “a bit of a problem” because he went to prison soon after.

The relationship, mostly on-off, went on for several years before she eventually married him—that’s when the relationship went sour.

“She didn’t like the life he’d given her, sitting around in nightclubs,” Jacky told the Hackney Gazette. “There were celebrities, but it was a false life, a criminal life.

“Her family were against it. Unfortunately her brother Frankie got involved with them as Reggie’s ‘wheels’ man. The Krays also hooked her father, Frank Snr, with a job in one of their nightclubs.

“Frances wanted an ‘exit’ from that sort of life once she sussed it out.

“But Reggie would never let her go—he was very possessive.”

Their marriage lasted two months, winding up in Cedra Court in Cazenov Road, Clapton, underneath Ronnie’s flat.

“It was a total disaster,” Jacky found. “She had a complete breakdown and took medication prescribed by a psychiatrist. She completely cracked up.

“Reggie kept coming round to the flat every night. She couldn’t go anywhere because he’d have her followed—she was trapped.”

Frances wound up in Hackney Hospital for three months for psychiatric ‘shock’ treatment “which made her forget what had happened,” Jackie discovered.

She was released after two months and went to stay with her brother in at Wimbourne Court off Murray Grove in Shoreditch, where she later committed suicide.

“Frances wrote suicide notes that made it clear she wanted to end her life,” Jackie reveals.“She chose to take her own life with an overdose.”

Her brother Frankie, who took his own life in 2011 while suffering throat cancer, never talked to the media about what happened, except that one interview 15 years ago.

“Reggie wanted to kill the mother after Frances died,” Jacky adds. “He blamed her for the whole thing, which was ridiculous.

“He wanted someone to blame—anybody but himself.”

Jacky Hyams became familiar with the Krays through her father, street bookie Solly Hyams who opened a betting shop off Petticoat Lane when his dodgy livelihood went legit in 1961.

He knew the twins as teenage boxers who got into trouble with the law as teenagers in 1949 for GBH in a gang fight outside a Hackney dance hall. The Krays asked Solly, with his reputation as “a bit of a scribe”, to write a letter to the Old Bailey as a character reference. He wrote it as a favour—the Krays never forgot a favour.

Producer Brian Helgeland’s movie Legend, filmed last summer around Bethnal Green, Whitechapel and Clapton, is premiered in Leicester Square before going on general release on September 9.

Among those turning up at the premier are people who knew the Krays well—like former 1960s Fleet Street pin-up Maureen Flanagan, now 74 and running Hackney’s Paragon Trust charity shop in Wells Street raising funds for St Joseph’s Hospice in Mare Street, and EastEnders and Carry On star Barbara Windsor who grew up in Shoreditch.

Emily Browning plays tragic Frances, with Tom Hardy as both Kray twins.

Jacky Hyams’ book, Frances Kray—the Tragic Bride, originally published last year, comes out this Thursday in paperback (John Blake Publishing) at £7.99