Mayor of London Boris Johnson is facing criticism after making reference to US president Barrack Obama "part-Kenyan" heritage.

In an article published by The Sun, the Conservative MP for Uxbridge and South Ruislip was commenting on Obama's intervention in encouraging Britain to stay in the EU ahead of June's referendum.

MP Johnson suggests Obama, who is on a three-day visit to the UK, may have an "ancestral dislike of the British Empire" after making reference to his Kenyan heritage.

He wrote: "Some said it was a symbol of the part-Kenyan president's ancestral dislike of the British empire - of which Churchill had been such a fervent defender."

His comments were met with a barrage of criticism on social media, with some accusing the exiting Mayor him of racism.

Labour MP for Hayes and Harlington and Shadow Chancellor John McDonnell tweeted to accused Johnson of "dog whistle racism" and demanded he withdraw the comment.

West London MP for Ealing and Southall Virendra Sharma called Johnson's comments "despicable".