Prisoners are to be locked in their cells every Friday afternoon because of a government cash squeeze.
Inmates will spend more time in their cells rather than exercising, working or taking classes than at any time for almost 40 years.
The Prison Governors' Association (PGA) said it had been forced to order the closedown because of a Treasury demand for a 3 per cent cut in costs.
Paul Tidball, the PGA chairman, said: "This is our best way to meet that saving next year. Prisoners will be spending more time locked up than they were in 1969 from April next year."
Juliet Lyon, the chief executive of the Prison Reform Trust, told MPs that the cost of building three super-prisons was likely to be double the 1.2bn bill announced recently by Jack Straw, the Justice Secretary.Reuse content