ISG is underway with two major projects valued at £135 million, as part of the Ministry of Justice’s £4bn investment programme to create an additional 20,000 prison places across the UK.

The schemes at HMP Guys Marsh in Dorset and HMP Liverpool were procured through the Crown Commercial Service Framework.

ISG has commenced the £79 million project to build two, two-storey houseblocks, a new extension and deliver a general refurbishment programme at HMP Guys Marsh. The new houseblocks, one with 122 cells, the other with 59, will increase capacity at the Dorset prison by 31%.

Designed to be net zero carbon in operation and achieve a BREEAM Excellent environmental performance rating, the new house blocks feature air source heat pumps and LED lighting. Over 70% of the construction materials used are sustainably sourced, with the team utilising a Design for Manufacturing and Assembly (DfMA) construction approach to reduce the project programme and increase efficiencies.

The decarbonisation project philosophy extends to ISG’s site accommodation, where 95% of the power required to operate temporary site cabins is derived from renewable energy sources. During the groundworks phase, vehicles will be powered by sustainably sourced Hydrotreated Vegetable Oil (HVO), which will deliver a 90% reduction in CO2 emissions, when compared with traditional diesel-powered plant.

ISG is also building on its six-year partnership with HMP Liverpool, where the contractor has worked to modernise and upgrade accommodation at the prison, parts of which date back to the mid-nineteenth century. This latest £56 million scheme sees ISG deliver a full refurbishment in support of a proposed change in status at the prison from a Cat B to a Cat C facility.

The comprehensive programme includes site wide electrical infrastructure upgrades, supplemented by new highly efficient boilers, the restoration of all wings, and the addition of a new workshop. These upgrades will support the prison’s ambitious sustainability targets and reduce ongoing maintenance works in the long term.

Alistair McNeil, ISG’s sector director, said: “The significant expansion and investment in the UK’s prison estate is a major undertaking, and the MoJ should be recognised for its bold and innovative approach to the modernisation and expansion of its estate. Through our work with the MoJ and other contractor partners, working across the framework, we are consistently delivering better built outcomes, benefiting the prison population and wider society.

“Our projects at HMP Guys Marsh and HMP Liverpool not only address a need for prison places but will also support government carbon reduction targets, delivering buildings that cost less to run and maintain in the future.”

ISG was recently appointed to the MoJ’s five-year, £2.5bn constructor services framework and is currently working on the upgrade of HMP Birmingham. ISG is also one of four project partners on the MoJ’s £1bn New Prisons Programme alliance.