The number of prisoners has reached an all-time high, official statistics showed on Friday afternoon.
Ministry of Justice figures show England and Wales’ prison population is at a record 85,578 - an increase of 175 since 2010.
Justice Secretary Ken Clarke has previously said the rise in prisoners was "financially unsustainable".
"It is just very, very bad value for taxpayers' money to keep banging them up and warehousing them in overcrowded prisons where most of them get toughened up."
Frances Crook, director of anti-prison group the Howard League For Penal Reform said it was a sign of "failure":: "As the prison population reaches an all-time high, it is more important than ever to address our failing penal policy. Every week we cram hundreds more people into our already bulging jails, only for people to leave prison unchanged and to go back to crime.
“Prisons are awash with drugs, violence and arson and this is inflicted on local communities when people leave prison. The answer to rising prison populations is not to build more failing jails. This ceaseless growth in prison numbers is untenable and I implore the government to bite the bullet and find a strategic way to reduce the prison population by putting an end to short term prison sentences.
“A record prison high is a sign of failure, not success.”