Image caption The RAF has bought 14 of the aircraft under a 27-year contract worth £10.5 billion

The RAF's largest aircraft has been officially unveiled and named Voyager ahead of its first public appearance at the Royal International Air Tattoo.

The dual role air-to-air tanker and transport plane has a 60-metre (197ft) wingspan and is nearly 60 metres long.

It can carry almost 300 troops more than 6,000 miles and will replace the long-serving VC-10 and Tristar.

At a naming ceremony at RAF Fairford in Gloucestershire, Defence Secretary Liam Fox called it "magnificent".

He said: "This magnificent aircraft is the future for the RAF's air-to-air refuelling and passenger transport capability for the coming decades.

"Voyager, together with the C-17, C-130J and the A400M transport aircraft, will provide the RAF with a truly world class fleet of aircraft, underpinning the global reach that is vital to our operations."

Voyager Can carry out air-to-air refuelling of another aircraft with 100,000 litres of fuel

Has a refuel rate of 5,000 litres per minute

A garage forecourt petrol pump can pump fuel at 40 litres per minute

The RAF has bought 14 of the aircraft - a converted Airbus A330-200 airliner - under a 27-year private finance initiative contract worth £10.5bn with the AirTanker consortium.

The service will provide training and maintenance, as well as new purpose-built buildings at RAF Brize Norton in Oxfordshire, the RAF's air transport hub.

The Chief of the Air Staff, Air Chief Marshal Sir Stephen Dalton, said: "As we have seen in Afghanistan and Libya, an effective air-to-air refuelling and transport fleet is an essential force multiplier in this era of expeditionary warfare.

"Voyager, when it enters service later this year, will excel in these roles by not only increasing our air-to-air refuelling capability but also by substantially improving our strategic airlift capacity."

The Royal International Air Tattoo is the world's largest military air show and celebrates its 40th anniversary this year.