Sir Keir Starmer has spoken to Volodymyr Zelensky to express support for him “as Ukraine’s democratically elected leader” after Donald Trump claimed he was a “dictator”.

A Downing Street spokesperson said the Prime Minister had called Mr Zelensky on Wednesday evening and said it was “perfectly reasonable to suspend elections during war time as the UK did during World War Two”.

The call follows a day in which Mr Zelensky had traded barbs with Mr Trump, leading the US president to post a diatribe on his social media site, TruthSocial, in which he claimed his Ukrainian counterpart was “a dictator without elections”.

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Earlier, Mr Trump had suggested that Ukraine had started the current conflict in Russia, and falsely claimed Mr Zelensky had an approval rating of 4%.

In response, Mr Zelensky said Mr Trump was living in a “disinformation space”.

Other UK figures have also hit out at Mr Trump’s comments, with Conservative leader Kemi Badenoch saying Mr Zelensky was “the democratically elected leader of Ukraine who bravely stood up to Putin’s illegal invasion”.

Liberal Democrat leader Sir Ed Davey said Mr Trump’s comments “must be where the line is drawn” and hoped “the whole political spectrum” in the UK would “speak with one voice in opposition to Trump’s lies”.