David Cameron has said economic sanctions against Burma should be suspended in recognition of the changes taking place in the country.
The prime minister spoke after a meeting with pro-democracy leader Aung San Suu Kyi in Rangoon.
Suu Kyi welcomed his call and said the suspension of sanctions would "strengthen the hand of the reformers".
Cameron is the first Western leader to visit Burma since her success in a series of parliamentary by-elections.
Earlier, the prime minister met President Thein Sein and said the government had to demonstrate that moves to democracy were "irreversible".
Burma is the final leg of the prime minister's tour of South East Asia promoting UK interests.