As this morning we await smoke signals from Brussels as to whether the Prime Minister has his deal or not, minds are already turning to the impact of the upcoming referendum on domestic political fortunes.

The impact on the Conservatives has long been discussed. The party is split down the middle on Europe and any hope of maintaining a united front over the next four months is zero. Their best hope is that the debate is conducted with civility, and that wounds can be healed once the campaign is over. The resignation from the party of prominent activist and commentator, and ConHome Founder, Tim Montgomerie, shows just how hard that will be to achieve. Montgomerie’s departure wasn’t only about Europe, but it was a factor, and it shows for some how the subject is a non-negotiable article of faith.

The impact on Labour will be different, and is more about their electorate. Whilst Labour MPs and activists are pretty united in their support for Remain, Labour’s electorate is much more split. The risk for the party is that large numbers of its supporters side with Leave, and vote for UKIP, rather than Labour, for the first time. And all the evidence shows once you’ve sided with a party once, it becomes habit-forming. We saw in May the damage losing votes to UKIP can do to Labour, and the referendum could further cement what already looks like a long-term trend.

The one thing that is clear is that after this referendum, British politics will never been the same again. The question is so fundamental than new alliances will be made and historic ones broken. By this time next week, we will almost certainly have a date confirmed and a campaign underway. Let the grand battle commence…