US President, Donald Trump has said he believes Britain can have a “very very substantial trade deal” with the US after it leaves the EU.
Mr Trump spoke to business leaders at a meeting co-hosted by the British Prime Minister on the second day of his State visit.
The pair are now meeting for talks, with contentious issues such as doing business with Huawei on the agenda.
Protests are expected across the UK with Labour leader, Jeremy Corbyn due to address a rally in London.
Mrs May is also expected to set out the UK’s position on climate change and Iran during the meeting with the president at Downing Street.
The breakfast meeting of five British and five American firms, senior ministers and officials at St James’s Palace was held in a bid to boost trade links.
Mr Trump said he believed there was scope for further expansion of trade between the US and the UK.
“I think we will have a very, very substantial trade deal,” he told Mrs May.
“This is something you want to do and my folks want to do,” he added.
Mrs May said there were “huge opportunities” for Britain and the US to work together in the future.
“It is a great partnership but I think a partnership we can take even further,” she told the president, adding: “Of course that is with a good bilateral trade deal.”
The US president is set to hold talks with Conservative leadership hopeful Michael Gove, according to sources close to the environment secretary.
Mr Trump praised Mr Gove’s leadership rival Boris Johnson ahead of his visit to the UK.
A source close to Mr Gove told reporters, “Nothing has been fixed yet” but added: “Mr Gove was asked last night by Mr Trump’s team if he would be able to meet the president today. He said yes.”
Thousands of people are expected to join protests against Mr Trump’s visit on Tuesday.
A “national demonstration” in London’s Trafalgar Square began at 11:00 BST (06:00 Eastern Time), while protests are also planned in Birmingham, Stoke, Sheffield, Glasgow, Edinburgh, Chester, Leicester, Oxford and Exeter.
The Metropolitan Police said 3,182 officers have been deployed to police the president’s visit on Tuesday and to “ensure the safety and security of the public”.
We were promised a carnival atmosphere but it feels like we’re still waiting for the bongos to arrive.
What we do have is British satire on display for the masses of TVs crews and cameras from around the world.
Outside the House of Commons, there’s the Trump baby Blimp grasping his mobile phone poised to be launched in to the grey skies.
Two men are selling toilet paper branded with Mr Trump’s face – “America’s number one for your number twos” at two for £5.
And there’s a man dressed as a gorilla, with the face of Mr Trump locked in a cage alongside a jail-suited Boris Johnson, his blond hair uncannily like Mr Johnson’s own.
Not so funny are the more serious protesters, carrying banners calling to Lock Him Up and another saying Trump is a danger to the world.
A group of work colleagues on holiday from Belgium gave up a day taking in the sights of London to join the protest.
“He called Brussels a hell-hole,” said Deborah Debbaudt, from Ghent. “We just don’t like him.”
Alex Kenny, who will join the Stand Up To Trump protest in the capital, told reporters that Mr Trump’s views are “destabilising and polarising the world”.
“All people representing different strands today are coming together to show people in America that we do stand in opposition – not just to the person, but the ideas and the kind of world view he wants to put forward,” he said.
Labour leader Mr Corbyn, who boycotted the state dinner, will be joined at the rally by members of other political parties including the Liberal Democrats and the Green Party.