[dragonwriter]

> Yes, people forget that he'd already had two MPs jump ship to UKIP. If he hadn't promised a referendum the party would've split down the middle.

Arguably, allowing a partisan realignment wherein people would vote for representatives balancing views on the EU with other policy concerns would have been healthier for the nation (if more disruptive to the elites of the existing major parties) than trying to preserve the existing party structure by splitting out the EU issue to a referendum.

And, it probably would have been more likely to succeed at keeping the UK in the EU.