Contractors on the national prison framework have come together to maximise their purchasing power in the face of high materials prices.

Despite being rivals to win schemes, Kier, Wates, Willmott Dixon, Shepherd, Caledonian, Interserve, Shaylor and Morrison, have joined forces to deal with the effects of materials shortages and the resulting price hikes.

So far the contractors estimate that they will save £4m on steel products such as windows, cell doors, grilles, fencing and gates. They plan to roll out the strategy to other materials.

John Frankiewicz, Willmott Dixon’s chief operating officer, said: “With a clearly defined and visible workload over the next two years, we have used our combined economies of scale to make significant buying gains which will be reinvested into future programmes.”

We have used our combined scale to make significant buying gains

John Frankiewicz, Willmott Dixon

The Construction Products Association said in a report last month that earlier this year some products, including cement, timber, steel and glass, were in short supply. But it said the lack of supply was a short-term problem and did not indicate a long-term deficiency. However, with unprecedented industry growth, there is no guarantee that prices will not rise even more.

The contractors are under pressure to deliver 8,000 new prison places in England and Wales, as set out last year by then home secretary, John Reid, because of a severe shortage of existing places.

They must create additional places through refurbishment and extensions, as well as by building new prisons.