Scale of mental health homicides 'is being played down'

Campaigners have called today for authorities to stop playing down the scale of murders committed by mentally ill people as research suggested there were twice as many cases as official figures showed. Failing to address the issue properly could prevent lessons being learned, they said.

Professor Louis Appleby, who heads the National Confidential Inquiry into Suicide and Homicide by People with Mental Health Problems (NCISH), said around 50 people a year who had been in contact with specialist mental health care in the 12 months before the incident were convicted of homicide.

"If somebody were responsible for a homicide in which there were multiple victims that would count as one incident from our statistics – so the 50 cases a year are perpetrators, not victims. And, of course, there are a small number of cases where a person commits homicide and then commits suicide so there is no conviction, and those cases aren't included."

The film-maker Julian Hendy began studying mental health homicides in Britain following the murder of his 75-year-old father, Philip Hendy, in Bristol in 2007. He investigated more than 600 cases, in a documentary, of homicide by people with mental health problems, dating back to 1993, and concluded there were more than 100 incidents a year, compared with the 50 stated officially.

He said: "This is a shocking statistic. What happened to my father was completely devastating and to think it is happening to 100 families in Britain each year is truly awful. I know many mentally ill people are never violent but this underscores the need for prompt and effective treatment for the small minority who are. Mental health authorities should learn lessons from such tragedies and a first step would be to include all the victims in the statistics so we can understand the true scale of the problem better."

Marjorie Wallace, chief executive of SANE, said :"This brave film reveals the reality of under-treated mental illness while raising urgent questions about the way we treat such homicides.

"Unfortunately, to reduce stigma there is a trend to underplay the scale of these tragedies, but this prevents lessons from being learned," she added.

'Why Did You Kill My Dad?' will be screened on BBC2 at 9pm tonight