Clifford Hobbs, 47, was arrested yesterday on a European arrest warrant in the Malaga area.
Hobbs was set free in June 2003 when two armed men ambushed the van he was being taken to court in.
During the attack, the driver of the van was shot in the leg and a security guard travelling in the back was pistol-whipped across the face before a total of three men escaped on foot.
Co-defendant Noel Cunningham, who was also charged with plotting to steal from a Securicor van in Effra Road, Brixton in March 2003, remains at large.
Tony Peters, a remand prisoner who also escaped from the scene, handed himself in to police days later.
Hobbs remains in custody in Spain while the Metropolitan Police Service seeks extradition.