In April 2016, Mayor of London and Conservative MP Boris Johnson was accused of "dog whistle racism" by Shadow Chancellor of the Exchequer and Labour MP John McDonnell when Johnson suggested U.S. President Barack Obama held a grudge against the United Kingdom due to his "ancestral dislike of the British Empire" as a result of his "part-Kenyan" heritage, after Obama expressed his support for the UK to vote to remain in the European Union ahead of the UK's referendum on EU membership.