A spike in prison suicides needs to be urgently explained before it turns into a national scandal, the chief inspector of prisons has warned.
In an interview with the Sunday Times, Nick Hardwick said the sudden rise in suicides could be the result of reduced staff levels and the effects of Chris Grayling's controversial Incentives and Earned Privileges scheme, which bans prisoners being sent items through the mail, including books.
"I am not satisfied this is being given the urgency and priority it needs. Were these increases in deaths to happen in any other area, there would be an outcry," he said.
"It is really important the system doesn't try to explain this away."
Hardwick warned the prison service could be heading towards a scandal akin to that of the Mid-Staffordshire NHS Foundation Trust, where poor care led to the deaths of patients.
There were 89 suicides in 2013/14 - the highest figure for ten years. The number compares to 51 suicides in 2012/13.
Already this month, four prisoners have killed themselves.
Grayling's earned privileges scheme prompted an outraged campaign by penal reform activists and authors when it emerged that books had been included alongside luxury items like video consoles.
Prisoners are only able to access books from the prison library, which hold a very limited selection, or by purchasing them with money earned in jail.
But with the average prison salary standing at just over £8 a week and prisoners being forced to pay for all items from it, few are expected to opt for reading material with their limited funds.
Educational groups have warned that prisoners are struggling to complete courses because of the restrictions on prisoners being sent books.
The controversy comes amid concerns about limited staffing levels in prisons, with overcrowding and cuts to services meaning prisoner-staff ratios are reaching dangerous levels.
Writing on the ConservtiveHome website, Grayling said: "These are the kind of changes the public wanted to see. A regime that is more Spartan unless you do the right thing.
"And of course it's the kind of thing that left wing pressure groups hate. That's why they are trying to persuade the public that we have banned books and brought a halt to all rehabilitation."