Illegal gun factory weapons were 'used in some of Britain's most serious crimes'

They included eight murders and another 24 shootings, prosecutor John Price told Reading Crown Court.

He said it was 'impossible to overstate the significance' of the factory, uncovered in a police swoop alongside the M4 in Berkshire.

Mac-10 machine gun: A weapon similar to the one allegedly sold in the illegal arms deal

One of its organisers had convinced a legitimate arms dealer to sell him 90 replica Mac-10 machine guns by claiming he was working on a James Bond, it was alleged.

He and his accomplice then converted the replicas to real weapons which were sold to criminals, the jury was told.

Mr Price said the Mac-10 was designed and manufactured exclusively as a military weapon.

He said: 'It is used by specialist troops such as paratroopers and commandos. It is designed for the close-quarters killing or maiming of human beings and it has no other purpose.'

He said 41 of the Mac-10s had been recovered, but at least 38 were still in circulation.

Mr Price said the murders dated from the late summer of 2004.

One gun, recovered by police in South London, had been used to kill two people, and featured in three other incidents where shots were fired.

In all, there were 51 incidents where guns were fired in public and investigations revealed that they or the ammunition came from the M4 factory. They happened in London, Birmingham and Manchester

Gary Lewis, 38, of Bourne End, near Maidenhead, and Grant Wilkinson, 33, of no fixed abode, deny nine charges including conspiracy to convert an imitation firearm into a firearm, conspiracy to sell and transfer firearms and ammunition and possession of a firearm with intent to endanger life.

The jury was told the two men worked in what appeared to be a disused outbuilding. But police found a well-equipped a workshop, testing room and firing range.

The trial continues.