Keir Starmer last night vowed to move Britain closer to the EU, despite warnings it could alienate Donald Trump. The Prime Minister insisted a softer Brexit deal was ‘vital for our growth and security’ – and said he had ‘already made progress’ on a reset of relations with Brussels.

In the annual speech to the Lord Mayor’s banquet in the City of London, the PM insisted he could strengthen ties with Mr Trump at the same time, revealing that he had told the President-elect he would ‘invest more deeply than ever in this transatlantic bond with our American friends’.

Mr Trump has been a vocal critic of the EU and allies have warned that Sir Keir cannot expect a close relationship with the incoming administration in Washington if he cosies up to Brussels. Stephen Moore, an economic adviser to Mr Trump, said last month that Britain would have to choose between the EU and Washington, saying: ‘Britain has to decide – do you want to go towards the European socialist model or do you want to go towards the U.S. free market?’ Mr Moore said the U.S. would be ‘less interested’ in a new trade deal with the UK if Sir Keir forges closer economic ties with Brussels.

Some Labour MPs have urged the PM to accelerate closer ties with Brussels in the wake of President Trump’s victory, while Lib Dem leader has advised him to ‘Trump-proof’ Britain by cosying up to the EU. The PM last night insisted he could ride both horses at once, saying it was ‘plain wrong’ to suggest he would have to prioritise between relations with Britain’s most important ally and its biggest trading market. ‘I want to be clear at the outset,’ he said. ‘Against the backdrop of these dangerous times, the idea that we must choose between our allies – that somehow we’re with either America or Europe – is plain wrong. I reject it utterly. Attlee did not choose between allies. Churchill did not choose. The national interest demands that we work with both.’

In recent months, Sir Keir has tried to rebuild relations with Mr Trump following years in which Labour painted him as a Right-wing bogeyman. Last night he said he would never turn his back on the U.S., despite foreign secretary David Lammy once describing Mr Trump as a ‘tyrant in a toupee’. The PM said the U.S. had been ‘the cornerstone of our security and our prosperity for over a century’, adding: ‘We will never turn away from that.’

He said the ‘special relationship’ was forged on the battlefields of two world wars, adding: ‘This is not about sentimentality. It is about hard-headed realism. Time and again the best hope for the world and the surest way to serve our mutual national interest has come from our two nations working together. It still does.’ Sir Keir said that when Mr Trump ‘graciously hosted me for dinner’ in New York in September ‘I told him that we will invest more deeply than ever in this transatlantic bond with our American friends in the years to come.’ He added: ‘And we will rebuild our ties with Europe too.’

Sir Keir has invested heavily in strengthening relations with EU leaders as part of efforts to reset relations with Brussels. Ministers are said to be close to agreeing a deal which would allow young Europeans to travel and work in the UK, which they hope will open to door to a wider trade agreement. Last night the PM insisted he was not trying to reverse Brexit, saying the talks were ‘about looking forward, not back’. ‘There will be no return to freedom of movement, no return to the customs union and no return to the single market,’ he said. ‘Instead we will find practical, agile ways to cooperate which serve the national interest. But he said renewed relations with the EU were ‘on any objective assessment vital for our growth and security.’

And he accused the Conservatives of undermining Britain’s influence by souring relations with Europe and ‘demonising’ the European Court of Human Rights in Strasbourg as a ‘foreign court’. ‘None of this was aimed at seriously trying to solve the problems we face,’ he said. ‘And added together, it actively harmed the national interest.’ The PM defended recent efforts to thaw relations with China, saying Britain ‘can’t simply look the other way’ at the actions of the emerging superpower. ‘We need to engage,’ he said.

Sir Keir renewed his commitment to Ukraine, saying it was ‘deeply in our self-interest’. But, in an acknowledgement that an incoming Trump administration could pressure Kyiv to sue for peace, he suggested the aim now must be to ‘put Ukraine in the strongest possible position for negotiations so they can secure a just and lasting peace on their terms that guarantees their security, independence – and right to choose their own future’. Making the case for continued support for Ukraine’s military effort, he said the ‘future of freedom in Europe is being decided today’.

‘We face a near and present danger with Russia as an erratic, increasingly desperate aggressor, on our continent marshalling all its resources – along with North Korean troops and Iranian missiles – aiming to kill and to conquer,’ he said. The PM repeated his commitment to increasing defence spending to 2.5 per cent of GDP but again gave no timetable for when military funding might increase. With Mr Trump raising concerns about the financial contributions made by Nato members, Sir Keir said it was ‘vital that all European nations step up to protect our shared future’.