Anyone who is thinking of threatening us with a UKIP comeback is truly living in cloud cuckoo land.

Ukip was being dismissed as a threat right up until it won the EU elections.
Ukip could come back if the electorate feel sufficiently betrayed by the ruling class, or another populist party might emerge.

UKIP were never anywhere near threatening to take power.

A sufficient threat to force all parties to promise a referendum which has resulted in their worst nightmare.

. They were threatening to take enough votes away from the tories that Labour might take power.

Labour was equally threatened, otherwise they would not have promised a referendum too.