The armed forces have been hit by equipment and cost cutting on defence projects, Whitehall's spending watchdog has found.

Slow delivery means that troops are left to cope with ageing equipment.

Hercules C130K aircraft - one of the oldest planes in use by the RAF - has had its life extended by an extra year.

And a maritime reconnaissance and attack aircraft, the Nimrod MRA4, worth almost £3 billion, is nearly three years behind schedule.

Delays mean that Nimrod aircraft with over 33 years flying time will continue to be pressed into service until mid-2008.

The watchdog also found that just nine of the 25 Airbus A400Ms ordered by the Ministry of Defence will be fitted with electronic protection from missile attack.

The decision to cut back on the high-tech "defensive aids suites" (DAS) saved the government £319 million.

While DAS can be transferred from one aircraft to another the cost saving will limit the number of A400Ms that can be used in a hostile combat situation.

The watchdog branded the corner-cutting as a "trade-off capability for cost" and disclosed that new Airbus - a European defence collaboration - due to enter service in 2010 was already delayed by 16 months.

MoD officials have responded by saying the DAS numbers were based on an estimation of how many A400Ms were likely to be in active service at any one time - and that extra equipment requirements were under review.

"If circumstances change, this can be reviewed at any time," said a spokesman.

Minister with responsibility for defence procurement, Lord Bach, highlighted NAO findings showing some improvement in the defence project delivery.

"It is unrealistic to expect that smart acquisition will result in uniform success straight away, and we will experience somesetbacks," he said.

"Project delay remains an area of concern and we will continue to work hard with industry to improve our performance in this area."

But chairman of the Commons public accounts select committee, Edward Leigh, warned that the MOD was "storing up problems'' for future years".

"I am concerned that the MoD's progress may be masking deeper trouble ahead," he said.

"There were an unusually large number of new projects last year. Even at this early stage, on some of them there are indications that the rot is setting in."