Any mystery surrounding the death of community stalwart Bobby Martin was cleared up today as a coroner ruled he died of natural causes.

Bobby died aged 53 in July and was found by his ex-partner in his Tufnell Park home. He had been secretary of the Islington Survivors Network, where he worked with victims of historic child abuse, and was also director of outreach organisation Crying sons, helping young men leave gang life.

Today an inquest at St Pancras Coroner’s Court heard his former partner Sharon Martin became worried when she didn’t hear from him for “several days”, despite her texting him 13 times. She went to check on him at his Crayford Road address on July 16, where she found him dead.

The court heard Bobby and Sharon married in 1999 and separated “approximately five years ago” – but they had remained close and she still had a key to the house.

One family member, too distraught to even give her name, told the Gazette: “We are just totally devastated and we love him so much.”

Bobby’s nephew, Dan, added that the heart condition that killed him “is a family sickness”, that has claimed the lives of five other relatives.

In her post-morterm report, pathologist Liina Palm suggested Bobby’s cause of death was “indeterminate”.

But, interpreting her notes, coroner William Dolman said: “Having reviewed all the papers and looked at the post-mortem report I have found the exact cause of death, which the pathologist found but didn’t put in her case – it was definitely natural causes.”

He said Bobby “hadn’t had a heart attack but the heart was not healthy”.

And in his determination, the coroner added: “Although Dr Palm doesn’t write down the cause of death, having read the report with care, on the balance of probability I can give a cause of death based on those findings of acute pericarditis [an inflammation of the sac surrounding the heart] and, contributing, hyper-tensive heart disease [often associated with high blood pressure].

“So the cause of death is no longer a mystery.”

Hilary Hamnett, a senior toxicologist at Imperial College London, found no traces of drugs or alcohol in Bobby’s system.

Bobby “was a helpful and active man in the community”, said Sharon.

As well as his work with the survivors and Crying Sons, Bobby worked in the prison service for more than 13 years, where he helped rehabilitate inmates with substance abuse problems.

He also worked with the Home Office on its Ending Gangs and Youth Violence programme and served as chair of an independent advisory board for the Met’s gangs unit, Trident, following the 2011 riots.

He was due to start a new post at City Hall, helping to reform the Met’s controversial Gang Matrix, on the day he died.