JCB has clinched its biggest ever order after landing a contract – expected to be worth up to $140 million – to build a unique high-speed digger for the American armed forces.

It is the biggest, fastest and most expensive backhoe loader to ever go into production.

The machine is based on the high-speed Fastrac, with full suspension and anti-lock brakes.

The 12-tonne machine will have a top speed of 57 mph so it is fast enough to travel by road in a military convoy and is designed to be airlifted by a Hercules C-130 to wherever it is needed.

The deal to build the High Mobility Engineer Excavator (HMEE) to carry out front line engineering duties was clinched after a three year project which included JCB Managing Director and CEO John Patterson having a personal meeting with President George W Bush at the White House.

The four-wheel drive HMEE, powered by a 5.9-litre Cummins diesel can lift more than 2t and dig to a depth of almost 4m.

It has taken three years to develop and will be built by JCB in Savannah, Georgia.

The first armoured JCB super-diggers to join the ranks of the US Army will roll off the production line in 2007.