Two-thirds of prisons in England and Wales are overcrowded, figures revealed today, with some jails holding hundreds more inmates than they were built for.
Shrewsbury prison is the most overcrowded, at 179 per cent of normal capacity, followed by Swansea and Dorchester.
One of the largest prisons in England and Wales, Wandsworth in south London, is at 150 per cent capacity, with 1,650 inmates in spaces for 1107.
Overall there are 8,865 more prisoners inside the prisons system than it was designed to hold.
A total of 88 out of 140 jails were over their Certified Normal Accommodation level - defined as a providing "decent" standards.
The figures were compiled by the Prison Reform Trust, which warned "sentence inflation" meant too many people were being locked up.
Director Juliet Lyon said: "Pressure on public spending means that ministers can no longer afford to be complacent about prison overcrowding or the high reconviction rates it leads to.
"Simply building more prisons is an expensive dead end. The only way to reserve prison for serious and violent offenders is to cut out all unnecessary use of breach and remand and tackle sentence inflation and the growth of indeterminate punishments.
"Investment in prevention, treatment for addicts and mental healthcare would all pay dividends. After more than ten years of lurching from crisis to crisis it must be time for co-ordinated effort across departments and authoritative leadership."
Prisons can increase capacity by holding two prisoners in cells designed for one, or three in a two-person cell.
Last month nine prisons were so full they reached their absolute capacity - beyond which they are unsafe.
At the start of this month the prison population hit a record high, passing the 84,000 mark for the first time.
There are now 84,150 inmates in jails in England and Wales, up 3,000 in two years, despite around 2,500 prisoners being released early every month.
Ministers have pledged to increase prison capacity to 96,000 by 2014.
A Ministry of Justice spokesman said: "We will always provide enough prison places for serious and persistent offenders.
"The Government is pursuing an extensive building programme to expand the prison estate and expect to deliver an additional 1,750 places in 2009.
"Since 2007 a total of 4,929 places have been delivered as part of the Capacity Programme. The vast majority of these places, almost 4,700, have been provided in new accommodation.
"This is intended to provide us with sufficient space to modernise the estate and ensure prisons remain places of both punishment and reform."
Liberal Democrat Justice spokesman Paul Holmes said: "These deeply troubling figures highlight the chronic failure of this Government's prison policy.
"Labour's obsession with sounding tough on crime has left our prisons dangerously overcrowded with sky-high re-offending rates.
"Ministers must realise the bankruptcy of their approach and focus instead on what works.
"This means moving drug addicts and prisoners with mental health problems into more appropriate accommodation and treatment and investing in alternatives such as restorative justice."Reuse content