Adds details LONDON, Nov 22 (Reuters) - More than a thousand workers at British security company G4S have voted to strike on Dec. 4 in a dispute over pay, trade union GMB said on Tuesday, warning the walk out could cause cash shortages overthe Christmas period. The union said 97% of its G4S Cash members balloted had backed taking industrial action, as pay rises fail to keep pace with soaring inflation. "G4S Cash staff provide an absolutely vital service," GMB National Officer Eamon O'Hearn said.