Speaking ahead of the summit - her first major appearance on the world stage as Prime Minister - Mrs May declared that the talks with Australia showed Britain was “open for business”.

“As a bold, confident, outward-looking country, we’ll be playing a key role on the world stage,” she said.

“I’ll be talking to other world leaders about the opportunities for trade around the globe that will open up for Britain following Brexit. My ambition for Britain is that we should be a global leader in free trade.”

The trade success comes as Mrs May used her first major broadcast interview since becoming Prime Minister to rule out a snap general election before 2020.

In the interview, to be broadcast on BBC One on Sunday, she warned that Britain faced “difficult times” ahead, despite a succession of better-than-expected economic figures in recent days.

The Prime Minister insisted that controls on migration from the EU would be a vital part of her exit deal with Brussels.

David Davis, the new Brexit Secretary, will make a statement to MPs this week outlining the Government’s emerging position on the terms of withdrawal, she added.