By Andrew Hosken
BBC Today Programme
The mother of Olaseni Lewis is giving her support to a public inquiry
A charity has called for a public inquiry into what it says is the scandal of deaths in police custody.
Inquest - a charity that offers advice to bereaved people - says nearly 1,000 people have died in custody in England and Wales since 1990.
The charity and other campaigners say mental illness is the "hidden story" behind the problem.
Of 15 people who died in custody in 2011/2012, seven of those were thought to have mental health problems.
"That is a really disturbing number of people dying, said Deborah Coles, co-director of Inquest. "I think it's incumbent on this government to set up an inquiry and properly address the issues that these deaths raise about the use of the police for people with mental health issues."
One of the most disturbing recent cases concerns Kingston University graduate Olaseni Lewis, who died aged 23 after being restrained by police officers at the Bethlem Royal Hospital in Bromley, south-east London, in September 2010.
At first Seni, as he was known, admitted himself to the Maudsley Hospital in south London after suffering mental health problems. He was then transferred to the Bethlem.
"When he wanted to leave, about an hour later the police were called - an incident happened," says Olaseni's mother Ajibola. "I really don't know exactly what happened."
The family later learned that Mr Lewis had been taken to hospital after 11 police officers had been involved in his physical restraint. He was placed on a life support machine, which was switched off four days later when he was diagnosed with brain stem death. An inquest to determine cause of death has yet to be held.
Mrs Lewis added: "It's really disturbing that these sorts of things can be allowed to happen. It's been happening for years and it's something that people - ordinary people - don't get. They don't realise that these things are going on. Unless you are involved personally, you don't realise what's happening, and it's got to stop."
The Metropolitan Police, who are conducting a review of the case, declined to comment.
An inquest into the death of 25-year-old James Herbert is expected in April 2013.
He died in June 2010 after he had also been restrained by police officers after an incident in the city of Wells. Police were called when Mr Herbert, who had been suffering from intermittent mental health problems, had been seen acting strangely.
His father Tony Herbert, a businessman based in Coventry, said: "He was out in the town - one or two people called the police and said that someone was behaving strangely - but I want to stress again, never violently. People seemed to be concerned for him, rather than about him."
Following his restraint, James Herbert was taken first to Yeovil Police station, before being rushed to a local hospital, where he died.
"I still miss him," said his father. "It's nearly three years on. Bereavement in this situation is difficult because you don't really let them go. You desperately want justice for them. It's gut-wrenching, it's painful and it's unbelievably awful."
At one point there was anything up to eight officers holding Mikey down
In 2006, 10 officers in the West Midlands were cleared of charges in connection to the death of 38-year-old Mikey Powell.
In 2003, Mr Powell - a cousin of the poet and author Benjamin Zephaniah - died after he was restrained by officers during an incident outside his home.
An inquest jury concluded later that he had died as the result of "positional asphyxiation" - a form of asphyxia which occurs when the position of someone's body prevents them from breathing adequately.
Tippa Naphtali - Mr Zephaniah's brother and also a cousin of Mr Powell, said he had suffered intermittent mental health problems.
"He was just displaying some very odd behaviour indoors. He broke a window to get out of the house. Mikey ended up being restrained on the streets. Several more officers came. At one point there was anything up to eight officers holding him down, using various parts of his limbs were being held down.
Mikey later died at Thornhill Road police station in Birmingham.
Since 1969, there has been no successful prosecution of any police officer involved with a death in police custody, despite a total of 11 inquests reaching verdicts of unlawful killing.
Inquest believes there is a wider issue of police accountability.
It also believes that police need to address the disproportionate number of men from the Afro Caribbean and other ethnic minority communities represented in police custody deaths.
Assistant Chief Constable Dawn Copley of the Association of Chief Police Officers (ACPO), said the police were keen to learn lessons from the deaths.
"Each death in police custody is a personal tragedy," she said.
"There are increasing numbers of people who are suffering from mental ill health issues who come to the notice of police.
Often the very best people to deal with people suffering with mental ill health are specially-trained medical practitioners - not police officers - and the best place for them to be seen is on medical premises, not within police stations. Although clearly, where offences have been committed or people are apprehended in crisis-type situations, there is an inevitability that they come into police premises."
Andrew Hosken's report was first broadcast on the Today Programme on Monday 31 December 2012. Benjamin Zephaniah was the programme's guest-editor.