Doubt is being cast over the future of the army's controversial assault rifle at the centre of complaints about performance, according to a new official report.

The SA80 is the UK forces' standard weapon, but the troops say it sometimes jams in action.

Now a new report is recommending that several alternative weapons should be tested against the rifle to see if they offer better performance.

The report was commissioned urgently after Marines in Afghanistan claimed the new SA80-A2 had failed on three occasions - despite a �92m upgrade.

Its findings could mean either the government is preparing a big drive to persuade troops of the rifle's merits or it is planning to scrap the SA80 altogether.

'Confidence lost'

Defence Secretary Geoff Hoon has notably failed to give the rifle his full backing and several senior MoD figures want and expect to get rid of it.

The report is understood to say the SA80 is basically sound, but that troops have lost confidence in it, with dangers for morale and operations.

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

Paul Keetch

Paul Keetch, the Liberal Democrats defence spokesman, argues that British frontline soldiers should be given a replacement weapon.

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

'Waste of money'

Mr Keetch said: "The SA80 is fatally flawed. British soldiers deserve the best. The SA80 is not it - it must be replaced.

"It is no good blaming soldiers for inadequate maintenance of the SA80 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 a 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".

Defence spending

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.

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 SA80-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.