Speaking to marines at Downing Street, Mr Cameron said the "appalling" case in no way represented the spirit and proud history of the Royal Marines.
The sergeant, identified only as Marine A, was convicted over the shooting of the unknown man in 2011 on Friday.The conviction of a Royal Marine for murdering an injured Afghan insurgent should not "besmirch" the organisation, Prime Minister David Cameron has said.
Speaking to marines at Downing Street, Mr Cameron said the "appalling" case in no way represented the spirit and proud history of the Royal Marines.
The sergeant, identified only as Marine A, was convicted over the shooting of the unknown man in 2011 on Friday.
A retired commander has said he should be shown leniency when he is sentenced.
Addressing a group of serving and former Royal Marines raising funds for the Commando 999 charity, Mr Cameron said the Royal Marines had "one of the proudest histories of any in the world".
"We should not let that single incident besmirch the incredible work the Royal Marines have done, not only over decades but over centuries," he said.
The prime minister also thanked the marines for the "incredible work" they had done in Afghanistan, saying he believed "we will be able to leave that country with our heads held high."
'Friends brutalised'
A retired commander has said he should be shown leniency when he is sentenced.
Addressing a group of serving and former Royal Marines raising funds for the Commando 999 charity, Mr Cameron said the Royal Marines had "one of the proudest histories of any in the world".
"We should not let that single incident besmirch the incredible work the Royal Marines have done, not only over decades but over centuries," he said.
The prime minister also thanked the marines for the "incredible work" they had done