IT is not exactly an elegant flying machine, but the latest arrival at the Yorkshire Air Museum is certainly one-of-a kind.

For the new heavyweight head-turner among the exhibits at the museum at Elvington, near York, is a Chieftain main battle tank donated by Vickers Defence Industries, of Newcastle.

The 55-ton tank has already been repainted by volunteers at the museum and is the most powerful version of the Chieftain ever built.

A prototype version, it was fitted with a 1000 horsepower engine and transmission while the standard versions were 800hp.

The Chieftain 1000 was an attempt by Vickers, in partnership with the German companies of RENK, MTU and Krupp-MAK, to offer a significant performance and reliability upgrade for existing versions.

The first customer was to be the Kuwait government, immediately before the Gulf War.

The British Ministry of Defence also expressed an interest in it to replace vehicles used by Royal Marine and Royal Engineers units.

But the design was not fully developed, leaving the prototype as the most powerful Chieftain ever built.

In fact, the German engine and transmissions are still regarded as industrial secrets - and their manufacturers have donated them to the museum under strict conditions.

The museum now intends to complete the restoration of the vehicle, which still functions, with support from RENK, Vickers, and 150 Regiment Royal Logistics Corps.

The vehicle is expected to be of special interest to visitors attending various events, such as the Battlegroup North Wargames Show in May, and the Military Vehicle Rally being in June.