Mentally ill people are routinely forced to stand trial because the rules on fitness to appear in court are out of date, legal reformers have told the Government.
They are also warning that the defence of insanity – which was drawn up in the 19th century – is so anachronistic that it is shunned by defendants and should be scrapped.
The alert was sounded by the Law Commission, the body which recommends ways of modernising legislation.
Its intervention will put pressure on ministers to review the law to prevent vulnerable people suffering miscarriages of justice and being jailed when they will not be able to cope with prison.
The law regulating “unfitness to plead” is designed to protect people who are considered unable to understand and take part in court proceedings.
The Commission raised fears that the threshold of a defendant’s fitness to stand trial is set too high and warned: “This could mean that many people are tried when they should not because of their mental state.”
The defence of insanity relates to a person’s state of mind at the time of an alleged crime rather than when their trial takes place.
There are only around 30 successful insanity pleas in crown courts in England and Wales each year, probably because of the stigma attached to the defence.
In a discussion paper ahead of a final report, the Commission said: “Both the test for unfitness to plead and the insanity defence are founded on 19th century legal concepts. Neither of them has kept pace with developments in medicine, psychiatry and psychology.”
At the moment it is left to a judge to decide whether a defendant is able to plead and face a court.
But the Commission said the test applied by judges was outmoded and said: “If [it] were reformed, then there would probably be an increase in the number of people with serious mental disorder who are found unfit to stand trial.”
It also warned that England was out of step with other countries in the rules over the defence of insanity.
The Commission suggests it is replaced by a “lack of capacity” defence which says a person could not have avoided committing a crime because of a “medical condition…. recognised by professionals in the field”.
It would be defined as lacking the ability to make a rational judgement at the time of the offence or to understand that the act was wrong.
Being incapacitated by drink would be excluded as that would be regarded as a voluntary act.
The Ministry of Justice said: “The Government will consider and respond to the recommendations of the Law Commission when its final report is published.”
Mentally ill patients kept in police cells
Cuts to mental health services are putting the police under increased pressure to “pick up”, with a shortage of beds meaning vulnerable people have to be kept in cells under supervision for up to 48 hours, the Police Federation has said.
Spokesman Steve White said officers were “hugely frustrated”. “If someone gets sectioned… then the health service has to find a bed for them,” he said. “If you haven’t got a bed what are you going to do? We can’t provide the care that individual needs – it shouldn’t be left to the police.”