THE Kent by-election was aptly described as the Tory car hurtling towards the brick wall of Rochester at breakneck speed only, seconds before impact, for Labour to jump in the way.

Ed Miliband had been expecting his party to be on the sidelines, quietly watching on at the Tory wreckage in the wake of Ukip's famous victory but instead it was caught up in the tangled mass thanks to that terrible tweet from Emily Thornberry.

No wonder the Labour leader was described as "absolutely f****** furious" when he learned of the now ex-Shadow Attorney General's crass intervention. Of all the things that could have happened, a frontbencher insulting the very people Labour is trying desperately to cling onto to win power is arguably the worst.

Week in and week out, Mr Miliband's charge against his Old Etonian opponent is that David Cameron simply does not understand ordinary voters and only cares for the rich and privileged. Next week's PMQs should be interesting.

But while Labour's woes would have provided a silver lining, the black cloud still hovered over Tory HQ.

Mr Cameron promised to "throw the kitchen sink" at Rochester, visited five times as the Conservatives mounted a cavalry charge of ministers. They failed, and immediately rightwingers were calling for tougher measures on EU immigration.

True, a Tory defeat had been expected for weeks but the ramping up of the EU rhetoric the PM has been engaged in of late is testament to the massive worries Conservative high command has about the impact Ukip could have on the Tories' electoral chances.

Just to make Nigel Farage's day complete, the Liberal Democrats' polled their worst result and lost yet another deposit.

As for Ukip, there was understandable hyperbole. Its leader insisted the anti-EU party could now become a major force in British politics. There was talk of holding the balance of power and Douglas Carswell, the Tory turncoat and the first of now two Ukippers at Westminster, insisted his party could now win "dozens" more seats and replace Labour as the official opposition.

Hang on. The UK's first past the post system is not easy for parties to rack up a host of seats. While Ukip might manage a handful, its real effect could be to deprive the Tories of seats they otherwise thought they might win and let Labour in.