Prisoners are to be blocked from seeking legal aid to bring “trivial” cases against the Prison Service under plans to be announced by the Government today.

Jack Straw, the Justice Secretary, is to act after a series of claims, including one in which a prisoner won a legal battle to have his haircuts paid for by the state while on day release.

Last year taxpayers footed a £1 million compensation bill after almost 200 drug-addicted prisoners sued the Government, claiming that denying them a heroin substitute breached their human rights. And two years ago a murderer who sexually assaulted his victim as she lay dying demanded £50,000 in compensation after having to “slop out” his prison toilet.

Mr Straw will tell MPs that he is to limit inmates’ access to legal aid funds to stop a rise in claims over jail conditions.

“There is a market being developed by imaginative lawyers,” he said last week. “Some of the claims are genuine grievances. If they are about in the liberty of a prisoner, or parole, of course they should be properly represented. There’s no argument there.

“Or, in the rare cases of someone who alleges they have suffered a miscarriage of justice, it’s really important that they are represented.”

Lawyers on such cases will be paid a fixed rate for the job rather than hourly. The Legal Services Commission is also to strengthen the rules on giving legal aid for cases so that in future they cases will onlybe funded only if there is a “realistic prospect” of a positive benefit to the prisoner.

A new quality requirement is to be introduced to ensure that law firms taking on prison law cases have the experience and expertise to do the work.

The changes are to be introduced from next July 2010 after a warning earlier this years from the Legal Services Commission that the growth in legal aid for prison work was “unsustainable”.

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