An RAF surveillance aircraft has been deployed in support of the French military action in Mali, the Ministry of Defence said.
Prime Minister David Cameron pledged extra help for the mission this week amid concern over the threat posed by Islamist militants in north Africa.
The Sentinel - which usually carries a crew of five - has now been added to two C17 transport aircraft which have already been sent to the region.
Mr Cameron has insisted that Britain does not intend to deploy ground troops.
Defence Secretary Philip Hammond said: "As the Prime Minister has made clear, the UK supports France's decision to provide military support to the Malian government.
"He also said in the House that we would be looking at further French requests for additional logistical and surveillance support for this operation, over and above the two C-17s.
"Following NSC on Tuesday and discussions with the French, we have now decided to deploy Sentinel, a surveillance capability that has proved its worth in Libya and on an ongoing basis for counter-insurgency operations in Afghanistan.
"We have also agreed to continue to make available a C-17 heavy lift transport aircraft which has already provided important logistical support over recent days."
Officer Commanding 5 (AC) Squadron, Wing Commander Al Marshall, said: "Sentinel is deploying to provide a unique intelligence capability in support of French operations within Mali.
"We look forward to working closely with our French allies, building upon the working relationships established during training and previous operations such as Op Ellamy over Libya in 2011."
Mr Cameron spoke earlier this week of a global "generational struggle" against al Qaida-inspired Islamist terrorism in North Africa and said the UK should "thicken" links with region following this month's hostage crisis in Algeria.
He said Britain will provide troops to an EU mission to train the Malian military to take on Islamist militants who have taken over the north of the country.
The mission, due to deploy in February or March, is expected to include around 250 trainers and 250 force protection troops and Mr Cameron said the British contribution would number "in the tens, not the hundreds", with aides saying it would be at the lower end of that range.