DESCENDANTS of an iconic steam locomotive designer have kick-started the latest stage of a project to build a multi-million pound engine.

The Gresley class P2 engine Prince of Wales, which will take shape in Darlington, will be the most powerful steam locomotive in Britain.

Ben and Tim Godfrey, grandsons of Sir Nigel Gresley, the engineer who designed the world speed record holder Mallard, were at Tata Steel, in Scunthorpe, Lincolnshire, on Wednesday (May 21), where they oversaw production of 21-ton steel frames for Prince of Wales.

Prince of Wales is being built by the same team that built Tornado, Britain's first new steam engine for 50 years, which was completed in Darlington in 2008.

In February, Top Gear presenter James May made the first component for Prince of Wales - the smokebox dart, which will eventually be at the very front of the locomotive.

The process of manufacturing the chassis, which will form the basis for the engine, began last month.

Individual components will be assembled at the Darlington Locomotive Works, in Hopetown Lane.

Mark Allatt, chairman of the P2 Steam Locomotive Company, which is building Prince of Wales, said:

"The main frames of a steam locomotive are the parts upon which everything else is built, and so the importance of this milestone cannot be overstated.

"With the first part fabricated, courtesy of James May, we are thrilled to be able to have reached the stage of profiling the substantial pieces of metal that make up the locomotive’s frames at Tata Steel – and being able to declare that the project to build No. 2007 Prince of Wales is now well underway.

“Having already built one steam locomotive from the drawings with Tornado, the levels of support and interest that have been generated towards Prince of Wales have been nothing short of sensational.

"With backing from HRH Prince of Wales, high-profile celebrities, significant pledges and large numbers of monthly covenantors coming on board, we can demonstrate just how much progress we have made towards resurrecting this amazing design of steam locomotive from the annals of history.”

The P2 locomotives were the most powerful passenger steam engines to operate in the UK, designed by Sir Nigel Gresley to haul 600-ton trains on the arduous Edinburgh to Aberdeen route.

Public interest the the project is high, with more than £750,000 of the £5m needed already raised.