The UK will work with Donald Trump on economic and security issues, Sir Keir Starmer said as he insisted the “special relationship” will prosper with the new president-elect.

The Prime Minister congratulated Mr Trump on a “historic election victory” after American voters returned him to the White House.

Sir Keir was among the first world leaders to congratulate Mr Trump as the Government sought to build bridges with the president-elect after the Republican politician’s campaign filed a legal complaint about Labour activists supporting rival Kamala Harris.

Senior Labour figures, including Foreign Secretary David Lammy, have also been strident in their criticism of Mr Trump in the past.

But the Prime Minister said: “As the closest of allies, we stand shoulder to shoulder in defence of our shared values of freedom, democracy and enterprise.

“From growth and security to innovation and tech, I know that the UK-US special relationship will continue to prosper on both sides of the Atlantic for years to come.”

At Prime Minister’s Questions in the Commons, new Tory leader Kemi Badenoch urged Sir Keir to apologise for Mr Lammy’s 2018 description of Mr Trump as a “woman-hating, neo-Nazi-sympathising sociopath” who is “a profound threat to the international order”.

Mrs Badenoch also called on Sir Keir to back an invitation for Mr Trump to address Parliament and revive talks on a UK-US trade deal.

Sir Keir said: “Of course we will discuss issues of our economy with the president-elect, as we already have done.”

He told MPs: “We live in probably a more volatile world than we’ve lived in for many decades.

“It is absolutely crucial that we have a strong relationship, that strong, special relationship forged in difficult circumstances between the US and the UK.”

Mr Trump declared he had won a “magnificent victory for the American people” once it was clear he was on track to return to the White House as 47th president of the United States early on Wednesday.

That victory was later confirmed as a win in Wisconsin tipped him over the 270 electoral votes needed to defeat Ms Harris.

The return of Mr Trump to the White House could cause diplomatic headaches for the UK, with potential splits on global trade policy and the level of US support for Ukraine and Nato.

Mr Lammy has spent time seeking to form a close relationship with the Trump campaign, despite his history of outspoken criticism of his record – which also included calling him a “racist and KKK/neo-Nazi sympathiser” in 2017 and a “tyrant in a toupee” a year later.

“The UK has no greater friend than the US, with the special relationship being cherished on both sides of the Atlantic for more than 80 years,” Mr Lammy said on Wednesday.

Mr Trump told supporters that “America has given us an unprecedented and powerful mandate”.

He said that he would not let his backers down and that it is “time to put the divisions of the past four years behind us”.

Addressing a campaign party in Florida in the early hours of Wednesday, Mr Trump pledged to “fight” for “every citizen” and promised the “golden age of America”.

He added: “This is a magnificent victory for the American people that will allow us to make America great again.”

The president-elect has long complained about US tax dollars funding European security and has been highly critical about Nato members not spending enough.

He has also repeatedly claimed he would bring the war in Ukraine to an end, although he has not set out how he would achieve this.

Ukraine’s Volodymyr Zelensky was quick to congratulate Mr Trump and said: “I appreciate President Trump’s commitment to the ‘peace through strength’ approach in global affairs. This is exactly the principle that can practically bring just peace in Ukraine closer. I am hopeful that we will put it into action together.

“We rely on continued strong bipartisan support for Ukraine in the United States.”

Nato secretary general Mark Rutte said Mr Trump’s leadership “will again be key to keeping our alliance strong”, adding: “Through Nato, the US has 31 friends and allies who help to advance US interests, multiply American power and keep Americans safe.”

Addressing Mr Trump’s concerns about burden-sharing, he added: “Two-thirds of Allies now spend at least 2% of their GDP (gross domestic product) on defence, and defence spending and production are on an onward trajectory across the alliance.”

Former defence secretary Sir Ben Wallace said the return of Mr Trump should spur European Nato members to commit more to security, with a pledge to spend 3% of GDP.

“Whatever your feelings about the US election are, the best insurance for all our security is to invest in our own defence and security right across Europe,” he said.

Reform UK’s Nigel Farage, a leading supporter of Mr Trump, said the president-elect would be a “genuine radical”.

He told BBC Radio 4’s Today: “What you are going to see from this Trump administration, and I’m guessing that Elon Musk will be the man that is tasked to do it, is there will be a big fightback against the administrative bureaucratic state which is far too big, far too powerful and actually very undemocratic.

“What is very interesting about the Trump movement is that its critics call it all sorts of nasty names, the truth is in many ways it’s bringing Americans together.”