A soldier has been charged with conspiracy to supply firearms after he was arrested when he got off a train.
William Dempsey, 28, was detained near Carlisle rail station in August this year where he was said to be in possession of an Uzi machine gun, a shotgun and a pistol.
Dempsey was serving with the 5th Battalion Royal Regiment of Scotland, based in Canterbury, Kent, at the time of his arrest but is no longer in the Army.
He appeared before magistrates in Merseyside last week with three co-defendants, Barry Kelly, 33, of Darvel, Ayrshire, Craig Colquhoun, 20, of Barrhead, Renfrewshire, and James Ashdown, 31, of Canterbury, who face the same charge.
Defence sources said Dempsey's co-defendants were not serving soldiers and that the allegations did not relate to weapons from any Army barracks.
All four are in custody and are due to attend a preliminary hearing at Liverpool Crown Court on Thursday.
A spokesman for British Transport Police said: "Four men have been remanded in custody after appearing at Wirral Magistrates' Court.
"The men all appeared having been charged by British Transport Police with conspiracy to supply/acquire prohibited firearms.
"Their next appearance will be at Liverpool Crown Court on Thursday, December 20."