David Cameron begins a four-day tour of south-east Asia today, with the aim at sealing business deals worth more than £750 million.
The prime minister, accompanied by a group of business leaders from across the UK, says he wants to boost economic links with a part of the world Downing Street believes has "untapped potential" for Britain.
On what will be his first trade mission since the general election, Mr Cameron will become the first British prime minister to visit Vietnam.
The trip, which will also include a stop in Singapore, is aimed at increasing exports and forging trading links with rapidly-growing potential markets for British goods and services.
Mr Cameron will also push for progress on a free trade deal between the European Union (EU) and south east Asia, which Downing Street believes could provide a £3 billion-a-year boost to the British economy.
He will also seek to strengthen ties with the developing economies as a way of reducing the UK's dependence on European trade.
During his trip Mr Cameron will also discuss the growing international threat posed by the so-called Islamic State during talks in Indonesia and Malaysia.
He will also seek to build momentum for action to tackle climate change ahead of the United Nations summit in Paris at the end of the year.