A former Cabinet Minister who has been in jail himself last week challenged the Keswick Convention, a major UK evangelical rally, to get involved in the campaign to transform the country’s failing prison system.

Jonathan Aitken, a leading Tory, spoke about the “terrifying failure rate” in rehabilitating ex-offenders, reports the Baptist Times newspaper.

“In this country, seven out of every 10 released prisoners are back behind bars within two years,” Mr Aitken, who served a jail sentence for perjury eight years ago, is quoted as saying.

He continued: “Nine out of every 10 prisoners from young offenders institutions are back behind bars within two years. That is a terrifying failure rate and one that society as a whole should be thinking about, not just those responsible for the prison service. We are bad at one vital element in the prison system – rehabilitation.”

Mr Aitken declared: “Go back and ask your own church – does your church do anything in the way of prison ministry or after-care for prisoners? And if not, why not?”

He said it had been a “stunning revelation” to him that a third of prisoners could not read or write at all, and that another third could do so only with difficulty.

Literacy and skills training, post-release mentoring, and drugs rehabilitation were the other areas Aitken highlighted.

He said that volunteers from church and civic groups could help with such programmes.

After his time in prison, Mt Aitken studied theology and has written books on religion and spirituality.

As a minister in Margaret Thatcher’s administration he was once an enthusiastic proponent of arms sales.

Church groups are already involved in campaigns to reform the penal system and to move towards “restorative justice” as a more humane, Christian and effective approach to crime than punitive incarceration.