A team of technical experts is currently investigating how a £3 million exhaust system, in the Mechanical Engineering building, came to be built with galvanised, instead of stainless steel. The College were reluctant to reveal the cost of fixing the error, saying only that it was less than half of the original cost, meaning that whichever party is found liable could face a bill of up to £1.5 million.

The heavy-gauge exhaust system is supposed to ventilate toxic gases from engine test labs to the roof, and is part of a wider £13.5 million refurbishment of Mech Eng being carried out by the construction firm ISG.

The refurbishment was originally planned to have been completed in October 2010 but has faced delays and rising costs due to the exhaust system mistake and other additional work. The refurbishment is now intended to finish in the summer.

Steve Howe, Director of Capital Projects and Planning, said that when the mistake was discovered, “it was felt that [the exhaust system] wouldn’t stand up to long-term use”. He emphasised that the liability for the mistake was still unknown and didn’t rule out the possibility that Imperial would have to meet some of the extra costs.

He said that other work, in addition to the original £13.5 million contract, was also ongoing and said that the final cost of the refurbishment was still to be agreed.

ISG did not respond to a request for comment.