Media playback is unsupported on your device Media caption Theresa May: "A year ago few of us would have predicted the events ahead"

Post-Brexit Britain has a "historic" opportunity to take on a new role as the global champion of free trade, Theresa May has said.

In her first foreign policy speech at the Lord Mayor's banquet in the City of London, the prime minister promised to make globalisation "work for all".

A Downing Street source said UKIP's Nigel Farage would not have a role in building UK links with Donald Trump.

Labour said Mrs May had "no plan" for life in a post-Brexit world.

Speaking at London's Guildhall, Mrs May told the audience of leading business figures she envisaged a stronger role for government in developing an industrial strategy aimed at spreading wealth more evenly across the country.

She said that, after Mr Trump's victory in the US presidential election, "change is in the air", adding: "To be the true global champion of free trade in this new modern world, we also need to do something to help those families and communities who can actually lose out from it.

"Not standing inflexibly, refusing to change and still fighting the battles of the past, but adapting to the moment, evolving our thinking and seizing the opportunities ahead.

"That is the kind of leadership we need today. And I believe that it is Britain's historic global opportunity to provide it."

Image caption The Lord Mayor's banquet represents an annual chance for prime ministers to set out their thoughts on foreign policy

Image caption Hundreds of leading City figures attend the event

Mrs May said leaving the EU showed "how a free, flexible, ambitious country can step up to a new global role".

"This is a new direction - a new approach to managing the forces of globalisation so that they work for all - and it is the course on which the government I lead has embarked," she said.

Mrs May cited the UK's recent agreement to keep Nissan car production in the north-east of England and the development of a global hub to repair and maintain fighter aircraft in Wales as evidence of a competitive industrial strategy.

Image copyright PA Image caption Nissan and other firms have benefited from an activist industrial strategy, Mrs May said

Mrs May, who has called for more employee representatives on company boards and greater disclosure about corporate pay, also pledged to crack down on unfair business practices which "undermine faith in capitalism and free markets".

The Guildhall speech is one of the major foreign policy and security addresses which the prime minister makes every year.

Carolyn Fairbairn, director-general of the CBI business group, said: "It's encouraging to see the government make a robust case for free trade. Working with business, it can ensure that the benefits help drive productivity, and increase living standards in all parts of the country."

But, for Labour, shadow lord president of the council Jon Trickett said: "Theresa May ‎has spent the early days of her time in Number 10 giving speeches about spreading opportunity and providing leadership but her actions have betrayed her.

"She talks about leading Europe. But has no plan for Brexit. She talks about extending opportunity. But Britain's working people are worse off. And she talks about transforming the economy. But all that is on offer is more cuts, poor investment and little, if any, growth."

Liberal Democrat leader Tim Farron said: "Theresa May is trying to have her cake and eat it. She talks about being pro-business but won't offer the one thing business leaders needs most: clarity on her plans for Britain's future with Europe. She can't have it both ways."

Meanwhile, Nigel Farage's meeting with US president-elect Mr Trump over the weekend meant he was the first British politician to meet Mr Trump since his election.

Image copyright @Nigel_Farage Image caption President-elect Donald Trump welcomed UKIP leader Nigel Farage at Trump Tower, New York

Some Conservatives are questioning Mrs May's refusal to entertain any role for the interim UKIP leader in building links with the US administration, but a Downing Street source played down any disquiet.

The source said any involvement for Mr Farage was "categorically not going to happen", adding: "Farage is doing a very good PR job of trying to make himself seem indispensible."

Asked whether he would hire Mr Farage to improve links with Mr Trump, former Chancellor George Osborne told ITV's The Agenda: "Absolutely not. I mean, Theresa May is a very sensible person who is not going to do that.

"The British prime minister or the British government cannot contract its foreign policy out to Nigel Farage."

Mrs May's spokeswoman told reporters the relationship between Mr Trump and the PM was "working well" following an initial phone call that was "very warm in tone".

Arriving in Brussels for a meeting with his EU counterparts, Foreign Secretary Boris Johnson there was "a lot to be positive about" following Mr Trump's election.

"It is very important not to pre-judge the president-elect or his administration," he added.