THE man who supplied huge quantities of guns to some of the country's most vicious criminals faces a lengthy jail term when he is sentenced at the Old Bailey today.

Registered gun dealer and former special constable Anthony Mitchell, 44, has admitted four firearms charges in which he supplied weapons to crooks, including Scotland's number one criminal, Glasgow gangster Paul Ferris.

Co-defendant Robert Bown, 46, also faces up to 14 years in jail on joint charges with Mitchell. Both admit conspiracy to sell or transfer prohibited weapons and conspiracy to sell or transfer firearms. Mitchell has also pled guilty to possessing prohibited weapons and transferring pro- hibited weapons.

Opening the prosecution case against Mitchell, Orlando Pownall said: ''Over a period of at least three years between 1994 and 1997 the defendant was concerned in the transfer of prohibited weapons, namely MAC-10 submachine guns and other weapons.

''A number of firearms have been seized from the address used by the defendant and elsewhere. Inspection of those weapons show he was closely involved in their supply.''

Both Mitchell and Bown were members of the Stone Lodge Gun Club in Dartford, Kent. In 1991 Mitchell confided in Bown that he sometimes sold illegal weapons to John Ackerman, another member of the club, Mr Pownall said.

He told Bown he had made #250,000 from illegal gun sales over the years. But Mitchell and Ackerman fell out when Ackerman paid for a consignment of guns with counterfeit money and Bown began acting as a middleman between the two.

In July 1996 Ackerman was told by Bown that MAC-10 machine guns, renowned for their ferocious killing power and nicknamed the Big Mac by US crack gangs, were available. Mitchell would get deactivated machine guns and make them workable by changing the breech block and firing mechanism, the court heard. He also supplied ammunition and silencers for the MAC-10s.

Police became aware of the gun ring when Joseph McAuley was arrested on a Glasgow-bound train at Preston for being drunk and disorderly. In his bag they found a pistol, ammunition and silencer.

Mr Pownall said: ''Ferris ran Premier Security Services in Glasgow and McAuley was an employee of the business.''

He received a four-year jail sentence and when police later arrested Bown he identified the weapon as one he had sold to Ackerman for Mitchell.

An operation was mounted by the National Crime Squad, Strathclyde police and Scotland Yard's Organised Crime Unit and in May 1997 they swooped on Ferris, 35, as he bought guns from Ackerman in Islington, north London.

Ackerman, who was jailed for six years, named Mitchell, of Baden Road, Brighton, Sussex, as the man who had supplied three MAC-10s, ammunition, silencers and detonators.

Mitchell, who lives with his common-law wife, was sacked as a Sussex special constable in 1993 when he was caught illegally importing ammunition from the USA.

Ferris, from Hogganfield Street, Glasgow, is currently serving a ten year sentence after being caught outside Ackerman's home with an armful of weaponry.