YESTERDAY Theresa May caught everybody by surprise when she announced a snap election in June.

It was a surprise, not just because (in theory at least) we are now supposed to have a fixed-term parliament, with elections every five years, but because this is precisely what she said she wouldn’t be doing.

But it’s not hard to work out why she, or more probably her advisers, decided otherwise.

Because, despite the appearance of impregnability, Mrs May has a parliamentary majority of barely 20, and with more than that number of Tory MPs still reluctant to leave the EU, she could not have felt secure that her final Brexit package would get through.

So, we’ll be having an election long before we know what sort of deal she has negotiated and voters will be asked to back an unknown final settlement.

Smart politics from her point of view but, perhaps not so for the rest of us.

Of course, it could not have escaped her notice that with her poll lead over Labour well into double figures, and a Labour Party still at war with itself, her chances of substantially increasing her majority, and leaving Labour much weaker, are pretty high.

And there’s another bonus for the Tories. The 20 odd Tory MPs being investigated for fiddling their election finances last time round will, probably now not face prosecution.

There is one tiny piece of good news in today’s announcement for Labour.

Mrs May’s snap election will be fought on the old constituency boundaries; the new ones were, by some calculations, going to cost Labour an additional 30 to 40 seats.

Based on today’s polls Mrs May is set to win a handsome victory in June but, as we have all learnt to our cost, in these turbulent times only predictions about the past are reliable.

  • Ivor Gaber is Professor of Journalism at the University of Sussex and a former political correspondent at Westminster.