MPs on all sides of the House of Commons united in paying tribute to Jo Cox, the MP for Batley and Spen murdered so brutally last Thursday in an apparently fascist-inspired attack.

The pain felt by her colleagues was evident and the praise for the “caring, eloquent, principled and wise” MP heartfelt.

It could not be diminished by noises from Nigel Farage about the tragedy being used for political purposes: Farage should have the grace to shut up, since few have done more to legitimise racism and fascism in British politics than he has — particularly following the disgusting anti-refugee poster his party unveiled last week.

But it seems a forlorn hope that Labour leader Jeremy Corbyn’s injunction — “we all have a responsibility in this House and beyond not to whip up hatred or sow division” — will be remembered for long.

Cox’s shocking death has led many to question the aggressive and scaremongering tone of political debate, and the finger has been pointed at this week’s referendum on EU membership.

The rise of the far right is, however, not restricted to Britain.

In France Front National leader Marine Le Pen regularly tops the polls. In Austria the far-right Freedom Party came within a whisker of winning the presidency last month. Fascists are far stronger in a number of European countries than they are in Britain — in Greece, in the Netherlands, in Hungary.

So this is not about Brexit.

It has been argued that the referendum has allowed racist prejudices to be expressed more openly than before, especially in the form of anti-immigrant poison spewed forth by the right wing of the Leave campaign.

But this drum has been beaten for years by both main parties.

Labour has had Gordon Brown’s “British jobs for British workers” and that god-awful “controls on immigration” mug Ed Balls once hoped to toast a 2015 election victory with.

The Tories have predictably been far worse, despatching “go home or face arrest” lorries in the coalition years and wallowing in the worst anti-immigrant sentiment since.

It goes right to the top: it was Prime Minister David Cameron who dismissed desperate refugees as “a bunch of migrants” and a “swarm.”

Similarly, Cameron was up to his neck in the revolting Tory campaign for London mayor, railing about Sadiq Khan sharing platforms with extremists and conniving at every hint that Khan was somehow a terror threat, which reached a low when the Daily Mail illustrated an article about the dangers of voting Labour with an image of the July 7 2005 bombings.

The Tory implication that electing a Muslim was tantamount to electing a terrorist was deliberate, and encouraged the repulsive gesture of Britain First’s Paul Golding, who turned his back on the newly elected mayor as the results were announced.

Cameron is probably free of such prejudice himself. Since Khan’s election he has had no problem in sharing platforms with the man he so recently reviled as dangerous.

But what may be a political game to the old Etonian in Downing Street has real consequences for real people.

If fascism is on the march across Europe, causes can be identified. A broken economic system traps tens of millions in unemployment, drives down wages and pensions and beggars public services from London in the west to Athens in the east.

Corbyn is right to insist that we must direct our anger against austerity for these problems, not immigrants. And he is right to point out that the policies of both the British government and the EU have brought us to this pass.

Neither a Remain nor a Leave vote will change either. Whatever happens on Thursday, the left must reunite to take the fight to the fascists and stamp racism out wherever it is found — and we must end the austerity nightmare putting the boot into workers across the continent.