A surveillance aircraft from RAF Waddington has been sent to Mali to support France’s military action there, the Ministry of Defence said.
Defence Secretary Philip Hammond said the Sentinel R1 aircraft “has proved its worth in Libya and on an ongoing basis for counter-insurgency operations in Afghanistan”.
Two British C17 transport aircraft have already been sent to the region.
Mr Cameron has previously said Britain will not deploy ground troops in Mali.
The Sentinel will be deployed on Friday from RAF Waddington in Lincolnshire to, initially, Senegal. The RAF has a fleet of five Sentinels, but only one is being sent to west Africa.