Criminal minions from west London who were instructed by prisoner masterminds using illegally-held mobile telephones how to buy and modify obsolete firearms into live-firing deadly weapons have been convicted alongside their paymasters.

Sherika Abbott-Holder, 27, of Ashbourne Road, Park Royal, was found guilty today of conspiracy to supply firearms with intent to endanger life at Woolwich Crown Court alongside co-defendant Emma Jones, 26, of Auriol Drive, Uxbridge, was found guilty today of conspiracy to supply firearms. The Met police is not releasing a picture of Ms Jones.

Leon Brown, 31, of Melville Road, Harlesden, previously admitted conspiracy to transfer ammunition.

The ringleaders were Paul Alexander, 58, an inmate at HMP Belmarsh in Thamesmead, south-east London, who previously admitted conspiracy to supply firearms and ammunition with intent to endanger life, and Carl Gordon, 27, a serving prisoner at HMP Belmarsh, who was found guilty on Friday of conspiracy to supply firearms with intent to endanger life.

Gym instructor Gordon, originally of Clare Road, Greenford, stabbed Michael Campbell, 21, of Chiswick, to death in Welstead Way, Turnham Green, in a dispute over a vandalised car and was jailed in April 2006.

Carl Gordon

Alexander and Gordon met at HMP Swaleside in Kent, where the former was serving an indeterminate sentence for numerous firearms offences and the latter was serving a life sentence for murder.

Detective Inspector Richard Mills of the Metropolitan Police's Special Intelligence Section, said: “During the period that Gordon and Alexander met in prison, they effectively became business partners, dealing in deadly weapons and ammunition. The firearms and ammunition they converted had the potential to cause great harm on our streets and there is no doubt London is a safer place as a result of this network being dismantled.

“This was a complex investigation by the Met’s Special Intelligence Section, which is committed to targeting criminal networks and bringing a successful prosecution. I would like to pay tribute to the detectives who have worked tirelessly to see this case to its successful conclusion.”

Alexander had knowledge of firearms and Gordon had links to organised crime and together they used mobile phones that had been illegally smuggled into prison to send messages to contacts on the outside.

The prisoners instructed their minions to lawfully buy obsolete firearms and taught them to convert the guns into live, and therefore now prohibited, weapons. Ammunition for these weapons was no longer being manufactured but  Alexander had the knowledge and ability to produce it and explaned to the foot soldiers how to produce the bullets.

In 2011, the police received intelligence suggesting Alexander and Gordon were communicating with the criminal fraternity via mobile phones.

The Special Intelligence Section of the Metropolitan Police launched Operation Propus, initially resulting in the recovery of 12 firearms and defendants being sentenced to a total of 28 years’ imprisonment for possession of firearms and ammunition.

Other defendants involved in the conspiracy included:

Alexander’s wife, Caroline Hunter-Mann-Purdy, 64, of Harwich Road, who Harwich pleaded guilty to conspiracy to supply firearms and Alexander’s step-daughter, Lullabell Purdy, 26, of Harwich Road, Harwich, who pleaded guilty to money laundering offences.

Fellow inmate David Joseph, 28, of HMP Belmarsh, pleaded guilty to conspiracy to supply firearms with intent to endanger life.

All eight will be sentenced on a date to be decided.