An official inquiry into the failures of an assault rifle used by the armed forces in Afghanistan has concluded inadequate maintenance and cleaning was to blame, it is reported.

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.

Clearly we do not want the armed forces armed with a weapon which is not working properly

MoD spokeswoman

The Sunday Telegraph claims the inquiry's findings have infuriated senior officers in the Royal Marines who have described the outcome as a "whitewash".

But the Ministry of Defence told BBC News Online the report was still under consideration by ministers and senior military officials, and there would be no comment on its findings at this stage.

"We have concerns that the rifle is not working," a spokeswoman said.

"Clearly we do not want the armed forces armed with a weapon which is not working properly.

Failure complaints

"But we will not comment on the report as it is still under consideration."

A team of weapons specialists was sent to Afghanistan from the Defence Logistics Organisation - the body that keeps the armed forces supplied with items like fuel, weapons and ammunition - says the Telegraph.

The DLO team's report says those weapons cleaned following the manufacturer's instructions performed "highly successfully", while those cleaned by the Marines by themselves had a significant number of failures.

The original SA 80

In service since 1985 Made by Heckler and Koch (UK) Fires Nato standard 5.56 x 45mm ammo Weight 4.98kg Length 750mm Muzzle velocity 940m/s Effective range 500m Cyclic rate of fire 610/770 rounds/min *Stats from MoD

The MoD spokeswoman said the armed forces had been given instructions on maintenance and cleaning of the SA80-A2 when was first issued in March.

But soldiers say the gun is difficult to clean properly in the field.

The new version of the SA80 - which has been the standard model for British soldiers for 12 years - was brought in especially early for the Afghan mission.

Defence officials said when it first came out that it was among the most reliable 5.56mm guns in the world.

Troops in Afghanistan - the first to actually use the SA80-A2 - complained the new model still jammed and could not cope with extreme heat, cold, sand or dust.

Armed Forces Minister Adam Ingram confirmed in the House of Commons that three official failure reports had been filed from Afghanistan