Ahead of President Donald Trump s state visit to the U.K. that begins Monday, Londons mayor and vocal Trump critic Sadiq Khan excoriated the U.S. leader in a Saturday op-ed likening him to the fascists of the 20th century and saying it was un-British to give him the red carpet treatment.

Writing in The Observer , Khan lambasted Trump for exploiting xenophobia, racism and otherness as an electoral tactic, and for lying deliberately and repeatedly to the public.

Describing the president as one of the most egregious examples of a growing global threat of far-right politics, Khan accused Trump as well as Hungarys Viktor Orbn , Frances Marine Le Pen and Britains Nigel Farage of not just using the same divisive tropes of the fascists of the 20th century to garner support, but also employing new sinister methods to deliver their message.

Khan urged U.K. Prime Minister Theresa May to issue a powerful rejection of Trump and the far-right agenda he embodies.

Its so un-British to be rolling out the red carpet this week for a formal state visit for a president whose divisive behavior flies in the face of the ideals America was founded upon equality, liberty and religious freedom, Khan said.

The mayor isnt the only Londoner making clear that Trumps visit isnt welcomed. Large anti-Trump protests are scheduled to take place during his time in the British capital. Tens of thousands of demonstrators are expected to flood the citys streets on Tuesday and the infamous Trump Baby blimp has been granted approval by Khan to take to the citys skies.