The Prime Minister spent the night in Camp Bastion, Helmand province – home to more than 5,000 British servicemen and women.
Addressing troops in the midst of a sandstorm, he announced that his promised doubling of the operational allowance for troops on operations overseas would go ahead next month, backdated to 6 May, the date of the general election.
"I want to put you front and centre of national life again," he said. "I want you to help me create a new atmosphere in our country, an atmosphere where we back and revere and support our military.
"What you are doing here will never be forgotten, it is great and important work, you are incredibly brave and professional in what you do."