Theresa May is to vow to renew the UK’s special relationship with the US “for this new age” as she prepares to meet Donald Trump for the first time.

She travels to Philadelphia later to address Republican leaders at an event attended by the US president.

She will tell them that after Brexit, a “sovereign, global” Britain wants to enhance ties with its “old friends”.

On Friday, Mrs May will be the first world leader to hold face-to-face talks with Mr Trump in the White House.

Post-Brexit trade opportunities, security and intelligence co-operation and the future of Nato are likely to feature significantly in the talks.

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Mrs May has said her goal is to build on the historic relationship between the two nations, underpinned by their shared values and common interests.

But she has said she “won’t be afraid” to speak candidly to Mr Trump on matters where they disagree, having criticised remarks the businessman has made in the past about women and Muslims.

Becoming the first foreign leader to be invited to visit the White House since Mr Trump’s inauguration has been seen as something of a coup for Mrs May.

The government is keen to capitalise on the US president’s strong personal and business links to the UK and his support for Brexit – which he has described as a “smart move”.

‘An opportunity and a risk’

Laura Kuennsberg, BBC political editor

Theresa May is walking into a meeting with the most unorthodox president in decades, a man who today she will flatter, calling for the US and UK to “lead together again” as he starts to “renew his nation”.

A man who has found huge popularity among millions of voters precisely because he doesn’t care for politician norms.

But also a man with whom Theresa May disagrees overtly on a very long list of issues, whose views millions of other voters are deeply worried about, who has just suggested he might support torture as president.

The prime minister believes that she can draw on the relationship and traditions between our two countries to talk frankly to President Trump, to disagree as well as discuss.

Her aides say “she’s not scared of anyone” and that the potential advantages of getting closer to the United States are well worth the risks of accusations of cosying up to a president who is not afraid of offending anyone – who has even made it a trademark.

Read more from Laura

In her speech to the annual Republican retreat on Thursday, Mrs May will stress the unique contribution that the US and UK have made to the modern world and the institutions that underpin it, such as Nato and the United Nations.

She will say that just as the two nations have worked hand-in-hand to “defeat evil” and to “open up the world” in the past, they now have an opportunity to “lead, together, again”.

“The UK is by instinct and history a great, global nation that recognises its responsibilities to the world,” she will say.

“And as we end our membership of the European Union, we have the opportunity to reassert our belief in a confident, sovereign and global Britain, ready to build relationships with old friends and new allies alike.

“So as we rediscover our confidence together – as you renew your nation just as we renew ours – we have the opportunity, indeed the responsibility, to renew the special relationship for this new age.”

Present for the president

Theresa May will present Donald Trump, whose mother was born in the Outer Hebrides, with an engraved quaich, a Scottish artefact symbolising friendship.

The shallow bowls were traditionally used in Scotland from the 17th Century as drinking cups.

First lady Melania gets a hamper of produce from Chequers – containing apple juice, damson jam, marmalade, Bakewell tarts and “cranberry and white chocolate shorties”.

Although the UK cannot begin to negotiate trade deals with the US or other countries until it leaves the EU, Mr Trump has said he wants a “quick” deal after that happens and the two leaders are expected to discuss future co-operation.

Ted Malloch, who has been tipped as a future US ambassador to the European Union, has told the BBC the outline of a free trade deal could be done in as little as 90 days.

“There won’t be a deal signed in the White House of Friday, but there could be an agreement for a framework going forward where people are empowered to have that kind of conversation behind closed doors,” said Prof Malloch, who works at Henley Business School.

“That’s very positive, I think, and it also sends a signal that the United States is behind Great Britain in its hour of need.”

But other economists have warned that although the UK and US are already significant trade partners, negotiating a bilateral agreement from scratch could take years and face many potential obstacles.

Mr Trump’s protectionist rhetoric in his inauguration speech and his apparent hostility to existing global trade deals – he has already withdrawn from the Trans-Pacific Partnership and urged major reform of the North American Free Trade Agreement (Nafta) – have raised question marks about his commitment to an equal partnership.

‘No blank cheque’

Labour has urged Mrs May not to give Mr Trump a “blank cheque” over trade, warning UK interests must be put first and there can be no question of watering down food safety standards and opening up the NHS to foreign procurement in return for concessions.

During Friday’s visit, Mrs May will present a hamper of produce from her Chequers country retreat to First Lady Melania Trump as well as an engraved quaich – a Scottish toasting cup – to the US president.

The groundwork for the two-day visit was laid before Christmas when two of Mrs May’s closest aides met members of the Trump transition team, while Foreign Secretary Boris Johnson has also held talks with members of the president’s circle.

Mrs May, however, will not be the first British politician to meet Mr Trump since his election victory.

He met former UKIP leader Nigel Farage in New York and was interviewed by former cabinet minister Michael Gove for the Times newspaper – meetings which are said to have dismayed some in Downing Street.

Mr Trump is expected to make a cameo appearance at the three-day Republican retreat in Philadelphia, an annual strategy event held behind closed doors.

Although the party also controls the House of Representatives and the Senate, Mr Trump fell out with many leading party figures during the presidential campaign.