Britain will send an extra spy plane to Iraq and Syria in the coming weeks to help provide surveillance in the fight against Islamic State militants, Defense Secretary Michael Fallon said on Thursday.Britain's Royal Air Force (RAF) carries out regular air strikes in Iraq but has so far limited its Syrian involvement to flying surveillance missions to gather intelligence.Earlier this month, Prime Minister David Cameron asked lawmakers to consider whether Britain should also join U.S.-led air strikes in Syria.Britain is buying three Airseeker Rivet Joint surveillance aircraft from the United States, the first of which is already operating in the Middle East along with British aircraft including Reaper drones and Tornado fighter jets."Our latest Airseeker plane will be delivered next month, seven months ahead of schedule, and will be operational shortly after that in the skies above Iraq and Syria providing essential support in the fight against ISIL (Islamic State)," Fallon told a Royal United Services Institute conference in London.Fallon likened the fight against Islamic State militants to the Battle of Britain, the 1940 air conflict between the RAF and the German Luftwaffe whose 75th anniversary is being commemorated this year."I believe we're fighting a new Battle of Britain. Once again, against a fascist enemy, an enemy prepared to kill its enemies and civilians alike," he said."The world is a darker place, darker clouds are massing on the horizon."