The government is being urged to abandon the army's controversial assault rifle at the centre of complaints about performance.

Liberal Democrat defence spokesman Paul Keetch said British frontline soldiers should be given a replacement for the SA-80 rifle.

For British soldiers to be deployed with a weapon that has operated below par for over a decade is scandalous

Paul Keetch

Marines in Afghanistan have said the new SA80-A2 guns failed on at least three occasions - despite £92m worth of modifications following complaints about the previous model.

An inquiry into the claims is believed to have concluded that inadequate maintenance and cleaning was to blame.

'Waste of money'

Mr Keetch said: "The SA-80 is fatally flawed. British soldiers deserve the best. The SA-80 is not it - it must be replaced.

"It is no good blaming soldiers for inadequate maintenance of the SA-80 when field tests have been fudged."

He said the £92m upgrade had been a waste of money.

Mr Keetch: SA-80 is fatally flawed

"More than three times the amount Man United paid for Rio Ferdinand," he continued.

In his letter to Mr Hoon, he wrote: "Confidence in your weapon is a prerequisite for any soldier.

"For British soldiers to be deployed with a weapon that has operated below par for over a decade is scandalous".

A series of problems with the previous SA80 rifle, including the weapon jamming in extreme temperatures, led to it being suspended from the Nato nominated weapon list in 1997.

Defence spending

Mr Keetch said that much had been made of the increase in defence spending to pay for high tech, computer-based systems needed to fight modern expeditionary warfare.

But he said: "Most soldiers would find the choice between 'network centric systems' and a rifle that works fairly easy to make."

Mr Hoon has already promised that claims that the SA-80-A2 misfires badly will be looked into.

Earlier this month he said that a specialist team in Afghanistan was investigating reports of problems with the rifle in dusty conditions and extremes of temperature.