UKIP - Send in the 'clowns'
This is the day when those dubbed "clowns, loonies, fruitcakes and closet racists" may find it hard to resist the temptation to laugh in the face of their detractors in the established political parties.
It is the day UKIP emerged as a real political force in the land.
The leaders of all other political parties will now be considering how to respond, what to say and what to do in the face of the party's rise.
UKIP has evolved over the two decades since it was created from an anti-EU pressure group into a fully fledged party which has now proved that it can succeed beyond European elections.
This is a more profound change than you might think. Before today a party created because of one issue and dominated by one man could, in theory, have simply wound up after a referendum on the UK's membership of the EU.
Many of its early backers might have concluded at that point - "job done".
Now, however, there will be UKIP councillors all over the country (there may even be some with a slice of power once all the results are in) who will insist they exist for other purposes. UKIP is not going the way of the Referendum Party.
For now their impact will be on other parties.
Tories on the right will claim that if only David Cameron had listened to them none of this would have happened. They will demand political red meat to woo back their former supporters.
To some extent it's already been offered - David Cameron has talked of a parliamentary vote on an EU referendum, he's announced a crackdown on immigration and a tougher prison regime has been heralded. So, what now?
Blairites will reheat their warnings that Ed Miliband has not extended Labour's support enough.
Some in his party will angst about their appeal in the South, some about their failure to convince their traditional white working class voters. He will respond, I suspect, with an attempt to forge a much clearer economic alternative.
The Lib Dems will be relieved that the spotlight is on someone else's problems whilst having to live with the fact that their party's problems are very far from over.
Nigel Farage has already proved that he is one of those politicians like Ken and Boris and Alex Salmond who can make his country smile. Now the clowns are bringing tears to their opponents' eyes. He's sure to see the joke in that.
PS: Having said all of this this let's not forget that UKIP did not win the elections. They look set to end the night with tens of councillors not many hundreds, unlike their opponents. It is extremely unlikely to run any council alone.
They have no MPs and, under our first-past-the-post system, it would be a major achievement to elect just one. Labour still won last night's by-election and the Conservatives look set to have the most councillors and run the most councils.
UKIP are putting down political roots. They are not about to challenge for power.