CONSTRUCTION work on the scaled-back 'super prison' at Thornton Hall is finally to begin in July, director general of the Irish Prison Service (IPS) Brian Purcell told the Sunday Tribune.

Preliminary work at the north Dublin site including construction of an access road and wall will begin in two months' time. A separate tender will then be put out to bidders for the contract to construct the prison. According to Purcell, construction on the actual prison is expected to begin in January 2011. The prison will not be operational until towards the end of 2015, he added.

Thornton Hall has already run up a bill of €41.8m in site costs, professional fees and security. The 2,200-inmate jail was to have been completed by the Leargas consortium, which included Kerry property developer Bernard McNamara, but negotiation between the IPS and Leargas broke down last May.

It was initially planned that Thornton Hall be built under a public-private partnership. The state now intends to pay for the prison in annual instalments over 25 years.

In 2005, the government acquired a 150-acre site at Kilsallaghan near Swords, Co Dublin, for €30m to construct the prison. The price per acre was far higher than any other in the area at that time, prompting sustained criticism of then minister for justice Michael McDowell. The site was to be the location for a new 2,200-berth prison to replace Mountjoy Prison, including the women's Dóchas Centre and St Patrick's Institution for young offenders.

A report by the Inspector of Prisons published in September 2009 found there was "inhuman and degrading treatment" at Mountjoy Prison.

It also found it was the most consistently overcrowded prison in Ireland. The report stated prison staff and management were working under impossible conditions due to chronic overcrowding. There were also problems with gangs and serious drug abuse at Ireland's largest prison, made all the more difficult by overcrowding.