Chuka Umunna.

Chuka Umunna as Labour leader here could cause the same undesirable phenomenon, as research has shown, occurred in the USA. In presidential elections, Obama's colour attracted ethnic votes but did not put off any customarily left of centre white voters. This clearly meant that his colour had a skewing effect on the results.
Frankly, I do not care what colour anyone is - but I want them to be accepted or rejected on the basis of their policies and integrity - not on shade of skin.