The UK has more state-of-the-art F-35 fast jets than pilots because of problems with flying training, the defence secretary has revealed.

The Ministry of Defence only has just over 20 of the next-generation £100m warplanes but cannot even man all of them, Ben Wallace confirmed.

“It’s a shambles,” a former Royal Air Force officer said.

Speaking to a committee of Peers, the defence secretary described the situation as “quite a challenge”, claiming that the deficit in pilots was also because the F-35 Lightning aircraft is new.

However, the Ministry of Defence formally announced its intention to buy the jets – a programme led by the United States and the US defence giant Lockheed Martin – back in 2006, and the first British pilot flew one in 2010.

The defence secretary conceded that the military’s flying training – beset by delays, with pilots waiting up to eight years to qualify instead of the target time of between two-to-three years – was a key factor.

“Our pilot pipeline is not in a place I would want it to be,” Mr Wallace said.

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He had instructed Air Chief Marshal Sir Mike Wigston, the head of the Royal Air Force, to sort out flying training as his only priority more than three years ago. Yet – as revealed by Sky News over the summer – it is still in crisis.

The F-35 is one of the UK’s most expensive and coveted equipment programmes, with the jets seen as bringing a new level of capability to the armed forces because of their sophisticated radars, sensors and other pieces of covert equipment.

Analysis: RAF’s three simultaneous crises put Air Chief Marshal Sir Mike Wigston under pressure

Britain originally intended to buy 138 of the F-35 jets over time.

However, at present it has only bought 27 of the aircraft.

One of them is out of use after crashing into the sea off one of the Royal Navy’s aircraft carriers last year, three more are in the US, leaving just 23 in the UK to be used by Royal Air Force and Fleet Air Arm pilots.