"The Prime Minister was clear that our support for Ukraine is unwavering - international borders must not be changed by force and Ukraine must have robust and credible security guarantees to defend its territorial integrity as part of any deal," a readout of a call from Starmer's Downing Street office said.

Donald Trump’s interventions over the Ukraine war have created a “viable” chance of a ceasefire but the UK stands ready to “increase pressure” on Russia if necessary, Sir Keir Starmer has said.