British Prime Minister Keir Starmer’s exhortation comes two days after U.S. backing of Ukraine appeared in jeopardy when President Donald Trump lashed out at Ukrainian President Volodymyr Zelenskyy.

President Volodymyr Zelenskyy arrived in the U.K. on Saturday, directly after his meeting with President Donald Trump and Vice President JD Vance in Washington, D.C.

Keir Starmer has been joined by Emmanuel Macron, Ursula von der Leyen and other key European leaders as they begin to arrive at Lancaster House for a London summit. The meeting will be the biggest European peace summit since the end of the Second World War.

The meeting has been overshadowed by the extraordinary scolding of Ukrainian President Volodymyr by President Trump at the White House.

NATO chief Mark Rutte has given new advice to Volodymyr Zelensky ahead of today's key talks between the leaders of 18 European countries following Donald Trump's Oval Office rant

Ukrainian President Volodymyr Zelensky joined leaders from Europe, Turkey and Canada in London on Sunday for a summit on the war in Ukraine and European security hosted by UK Prime Minister Keir Starmer.

At the pivotal London Summit on the Ukraine war, British Prime Minister Keir Starmer announced a peace plan for the war-torn country, which includes a one-month truce. The meeting of 18 European allies saw leaders promise more military aid to Volodymyr Zelenskyy.

NATO chief Mark Rutte has warned that it is vital for the future of European security that the US and Ukrainian presidents are back on speaking terms ahead of a crucial summit in London

Nato secretary-general Mark Rutte has also arrived ... Prime Minister Sir Keir Starmer (right) welcomes French President Emmanuel Macron to Lancaster House, London (Toby Melville/PA) Sir Keir had said earlier on Sunday that the UK will work with France ...

Sir Keir Starmer is gathering European leaders in London to forge a common position on ending the war in Ukraine.

This summit was in many ways an attempt by Europe to take some ownership of the diplomacy. In recent weeks, efforts to end fighting in Ukraine have been led by Trump speaking to Russian's President Vladimir Putin and at his Ukrainian counterpart Volodymyr Zelensky.