Dozens of health trainers have been recruited at 25 of Britain's toughest jails in a move which will cost taxpayers £400,000, according to the Sun newspaper.

Prisoners will be referred to the Exercise on Prescription scheme by prison doctors and will receive a free fitness assessment and an individual exercise routine devised by personal trainers, the paper says.

Tory MP Andrew Rosindell condemned the policy as unfair to taxpayers and declared that prisons should concentrate instead on providing healthy food.

The Romford MP said: "Frankly most people have to pay a lot of money to have a personal trainer and I do not think taxpayers should be paying for it.

"Law-abiding citizens should be pretty angry at the fact that criminals are getting it for free.

"If they fed them healthy foods, that is something that could be done to truly help them lose weight rather than giving them trainers."

But a spokeswoman for the Prison Service said: "The programme takes up no extra resources.

"The Prison Services encourages and facilitates physical education and team sports in every prison.

"As a means of promoting team-work, self-confidence, leadership, resilience, and individual and collective achievement it is a vital tool in the rehabilitation of offenders."

Trainers are also said to offer holistic alternative therapy instead of medication.

Niall Almond, who runs the programme at Everthorpe Prison in East Yorkshire told the Sun: "We've had some really good success stories."