Rehabilitation means taking pride in one's prison: David Cameron visits Wormwood Scrubs in 2012, when he promised a "tough but intelligent" approach to crime and punishment (photo: WPA Pool/Getty)

Our prisons are in their familiar state of overcrowded confusion — but are they in crisis? This question has moved up the national agenda in recent months. Predictably, the more pejorative label has been denied by the Secretary of State for Justice Chris Grayling and by the National Offender Management Service (NOMS) which runs most jails. But the chorus of Cassandras proclaiming or predicting crisis is being joined by anxious voices from beyond the ranks of the usual suspects.

The most authoritative sources of information on individual establishments are the reports of the Prison Inspectorate. The present holder of the office of HM Chief Inspector of Prisons is Nicholas Hardwick. Compared to one of his predecessors, General Lord Ramsbotham, who fired off his salvoes against NOMS managers like an artillery commander pounding the French lines at Waterloo, Hardwick is normally a restrained and constructive commentator on the system.

So it is disconcerting to find that this past summer Nick Hardwick issued a succession of highly critical reports on prisons as geographically diverse as HMPs Doncaster, Ranby and Isis, culminating in a 104-page blockbuster indictment of the "filthy and unsafe" Wormwood Scrubs, "HM Chief Inspector of Prisons Report on an unannounced inspection of HMP Wormwood Scrubs 6-16 May 2014".

There are consistently negative themes in the inspectorate's reporting. At all the above prisons, a high percentage of inmates felt at risk of violent attack. Suicide and self-harming rates are rising. The lockdowns of prisoners in their cells for 23 hours a day are becoming endemic. Staffing cuts and the introduction of new regimes mean that many officers are overstretched, often feeling frustrated at their inability to talk to, let alone help, the prisoners under their care. The Wormwood Scrubs report recorded that 80 per cent of the inmates were not spoken to by their officers during the week of the inspection.

To many, the Scrubs is the icon of the British prison system. I must have passed through its historic gates for at least 20 visits in various volunteering capacities during the past decade. "Tough but fair" would have been my verdict based on numerous conversations with both prisoners and staff. Unfortunately this opinion has to be revised after reading not only HM Inspector's September report on the jail but also a devastating critique by the former chairman of its Independent Monitoring Board, Angela Levin, Wormwood Scrubs: The Inside Story (Amazon, £9.99).

Ms Levin, a highly regarded journalist, joined the IMB, a watchdog body of voluntary supervisors for the prison, ten years ago. She describes herself as "one of those middle-class individuals who want to give something back to society . . . I am not a do-gooder with idealistic views on how to change the world." Her pages contain many compliments to the long-serving prison officers at the Scrubs. She makes the point that for many of them their work is "a vocation rather than a job". This will sound unlikely to viewers of Porridge, but her knowledgeable comment rings true.