Maybe Labour, and its old leader Miliband, like Messi? (4-6)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

LEFT (politically left-wing, for example the Labour Party) + FOOT (its old leader = Michael Foot, leader of the Labour Party in the 1980s) + ED (Ed Miliband, Labour MP and another former party leader). A footballer who predominantly kicks with his or her left foot, such as the Argentinian player Lionel Messi.