General election 2019: The predictably unpredictable campaign

The day before the election campaign starts in earnest, a bucket of cold, hard reality has been chucked over any Tories around the place who thought they might be able to set the terms of the debate, or control exactly what will happen in the next six weeks.

The man in the pinstripes who charms some Brexiteers stumbled into the first hideous mistake of this election campaign.

Jacob Rees-Mogg may have apologised for his insensitive remarks about what happened at Grenfell Tower.

But it is toxic for the Tories, playing straight into familiar accusations about the party that they can't understand, and therefore cannot seek to represent, ordinary people for whom life is sometimes a struggle.

Boris Johnson and his team are often accused of being simply a bunch of grown-up public school boys, who know little of the world beyond their gilded ascent to power.

Stereotypes of any type are often overcooked in politics, but wise Conservatives are very well aware they have an image problem on this front that is hard to shed.

Today's mistake just gave Labour all of the ammunition it needed to make the charge again and again, and then ensuing upset from some of their backers like Stormzy, the rapper and singer, which will have its own long-lasting half life on social media.

There aren't always very many moments of that elusive "cut through" in campaigns. This might just be the first moment this time round - although it is impossible to know yet if the upset over these remarks will shift any votes away from the Tories, or just enrage those who plan to choose other parties already.

And elections bring with them weeks, and tides and tides of news that can wash away early horrors or successes for any political party.

So far, so predictable - the parties all know well the view of the Conservative prime minister decades ago, Harold Macmillan, who warned what knocked parties off course was "the opposition of events". (Yes, apparently he never said, "events, dear boy, events", if you want to feel like a clever clogs).

But surprises can work in their favour too - and the Liberal Democrats are hoping the election will be just as unpredictable as the last few crazy years.

If you had heard a Liberal Democrat leader proclaim they were standing to be a candidate for prime minister not so long ago, you'd have wanted to check their temperature.

And yet every time Jo Swinson gets anywhere near a microphone, it's what she says.

Have things really become so strange that a party that got 12 MPs in 2017 is knocking on the door of No 10? Never, quite, say never.

Although in our first-past-the-post system, you may love or hate, it is vanishingly unlikely that a party could go from 12 MPs to the magic 326 that gives a party a majority, the power to govern, and to get things done.

So what are they on about?

Well, just as Jacob Rees-Mogg's dreadful gaffe will create terrible headlines for the Conservatives online and in the press, so too, the Lib Dems hope, the bold claim from Jo Swinson that she could genuinely end up in Downing Street creates noise and headlines, a sense of what might, just about, be possible.

The more familiar the message, the less far-fetched it might seem, so the theory goes, even though chat from some activists at the party's launch this morning was that getting back up to 50 or 60 seats or would be a pretty good night.

Expect the party leader, though, who believes she has a massive opportunity at her fingertips, to repeat her claim about No 10 again and again and again.

It may not be the most outlandish campaign we hear in the next few weeks.

Welcome to the predictably unpredictable campaign of 2019, and the prime minister hasn't even yet been to the Palace.