THE SHAKE-up that axed one of the region’s jails risks a surge in suicides and assaults, the Chief Inspector of Prisons has warned.

The move to build new “super-sized” prisons – which includes replacing HMP Northallerton - was criticised because they are harder to manage and have less experienced staff.

Nick Hardwick, the Chief Inspector, told MPs: “New prisons are difficult to establish and big prisons are difficult to run - so new big prisons are very difficult to run.

“I don't think it's a coincidence that we are seeing the highest level of self-inflicted deaths in prisons for many years - already about 50 per cent more this year than there were last year.

“The number of assaults in adult male prisons is up, the number of incidents at height is up.

“These incidents are terrible in themselves and I think that is a reflection of a system under real strain at the moment. I have concerns about what is happening.”

The warning, given to MPs on the Commons Justice Committee, comes amid plans to build a 2,000-place prison in Wrexham and, possibly, a further giant jail in London.

The cost-cutting shake-up spelt the end for 252-place Northallerton, built in 1783, which closed in December and is one of four prisons due to disappear.

Northallerton employed 138 Prison Service personnel and 52 other people such as health workers. The majority commuted from Darlington and County Durham.

The closure came hard-on-the-heels of other crippling public sector job losses at the nearby Rural Payments Agency, Natural England office and North Yorkshire County Council.

In evidence to the MPs, Mr Hardwick said: “What I hope ministers won't do is underestimate the difficulties of establishing any new prison.

“The new prisons established recently - Oakwood, Isis and Thamesmead - have all struggled and these difficulties are exacerbated the larger the size of the estate.”

The warning was echoed by the head of the Prison Governors Association, who warned the culture inside jails was changing, making rehabilitation more difficult.

Eoin McLennan-Murray said: “I think we will regret the day we thought big is beautiful. It certainly isn't unless you resource it correctly - and we are not doing that.”

The criticism comes after the closure of HMP Northallerton – rated as one of the best jails in the country – was also questioned by the National Audit Office (NAO).

In December, the NAO warned that high-performing prisons are being shut, only to be replaced by new jails where standards are far lower.

Its report noted that Northallerton held a performance rating of ‘4’ – the highest possible score – from the National Offender Management Service Agency.

And it received a mark of ‘14’ in a ‘healthy prison’ test run by HM Inspectorate of Prisons. The maximum grade was 16.