George Galloway has won a sensational victory in the Bradford West by-election with a 10,000 vote majority.

The scale of Galloway’s win, turning a safe Labour seat into a 10,000 vote majority, is without precedent in modern British politics. All those who oppose austerity and war should be walking a little taller this morning.

Galloway and Respect fought a campaign on two simple premises: opposition to wars abroad and opposition to austerity at home. In the absence of a Labour Party and Labour leadership able to effectively articulate either, a credible and electable campaign could storm home.

There are other factors involved, of course. By-elections notoriously attract protest votes and holding the seat will be a challenge, although one Galloway has vowed to meet. The scars of the war on terror have run very deep, with this Coalition government – and its neoconservative Cabinet members, like Gove and Osborne – on occasion surpassing even New Labour’s official Islamophobia. A principled defence of British Muslims is vital in such conditions and Galloway is rightly respected for his defence.

But a win on the scale achieved could not have been possible on the basis of that defence alone. You cannot win 18,341 votes in a Bradford constituency if only Muslims will vote for you – as if Muslims, in any case, voted as a bloc. Opposition to Britain’s wars runs deep across the whole population, with opinion polls consistently reporting over 70 per cent wanting the troops withdrawn from Afghanistan. The Pyrrhic victory in Libya has not shifted that opinion, and Galloway’s campaign shows the strength of opposition to war in Iran. The organised left has, to its discredit, underplayed in recent years the significance of Britain’s ongoing – if increasingly feeble – imperialist role. Galloway was absolutely correct to place opposition to war centre-stage in his campaign, and we should all take note.

Opposition to war has defined the breach with Labour for the last decade. It was the mass opposition to war in Iraq that set the stage for Galloway’s win at Bethnal Green and Bow during the 2005 general election, when a 10,000 Labour majority was transformed into a slender victory for Respect. That result was the result of a long, hard-fought campaign. Respect in Tower Hamlets was then a far more substantial force than it is today in Bradford, and it could draw more easily on an army of volunteers and activists. The victory in Bradford is all the more remarkable for being achieved so quickly and without that same large party machine.

The result can only be understood as the product of the opening of a second great breach with Labour: that of opposition to austerity. The Labour leadership and the Parliamentary party – with honourable exceptions – have fled the field of battle against the cuts, having never greatly desired the fight in the first place. The gap between Britain’s corrupt and squalid political class, and those they claim to represent – already large – yawns wider as a result. As austerity progresses, it will become a great chasm – and the well-respected Institute of Fiscal Studies estimates that we still have 88 per cent of the Tories’ scheduled spending cuts to get through.

This is the breach that can be seen across Europe. Traditional parties of working people – the social democratic parties – have already spent years imposing neoliberalism: the poisonous cocktail of privatisation and deregulation that helped drag us into the current crisis. In response to that crisis, they have – with rare exceptions – accepted austerity as the cure, turning like wild dogs on their own supporters. But where the real left has been able to offer a lead, standing firm in its opposition to spending cuts, it has been able to create new political possibilities: in France, where Left Front Presidential candidate Jean-Luc Melenchon is now polling 14 percent in some opinion polls; or Holland, where the anti-austerity Socialist Party polls 18 percent. Outside of electoral politics, the general strike in Spain yesterday and ongoing strikes and protests in Greece and elsewhere show the capacity of traditionally organised labour to become an effective resistance – echoed in the UK, in smaller fashion, by strike threats from truckers and baggage handlers.

It is this possibility of a new left that Galloway’s result herald. For Britain, it will combine opposition to wars abroad with opposition to austerity at home: genuine internationalism, and a radical defence of the gains working people have won. This new left may not arrive through the traditional channels, drawing in alongside militant trade unionists activists from Occupy, the anti-war movement, and some of the existing far left. But we can help it arrive, arguing for a radical left politics that holds to its principles, engages with the mass movements, and does not stand aloof from the real concerns of the working class.

We have here a weak and increasingly dysfunctional government. As they push harder into austerity, their weaknesses and dysfunctions are likely only to worsen. But for our side, battered by Thatcher and then bamboozled by Blair, the road to recovery is clearing. Two key tasks are ahead: first, to build from the great opposition to war a mass movement opposed to further interventions abroad; second, to build from the countless anti-cuts campaigns across the country a mass, national movement that can overwhelm austerity.