This is a fair counter example, but one also has to consider that (i) much of the referendum demand came from within his own party for ideological rather than practical reasons and (ii) he was able to implement it because the UK's electoral system and multiparty politics gave his party a clear majority with a minority of the vote .

Or put more simply: his personal standing within the party was threatened more than his party's electoral chances (UKIP votes were irrelevant in most Tory seats and took votes off Labour too in marginals), and he wouldn't have been in power anyway under a proportional system.

Ironically, EU Parliament votes being proportional probably played a major role in Farage deciding back in the nineties that he could try to win the Brexit debate from outside the Tory party too...