The Blair era was the perfect time for a left challenge – the Tories were totally out of contention and the government was frequently centre-right in all but name. In so many areas, be it the alliance with George Bush, the increase in PFI, the punitive measures against asylum seekers or refusal to increase taxes on the wealthy, Blair seemed to govern against his party rather than on behalf of them. While there were attempts to challenge Labour from the Left during those years, from the Socialist Alliance, to Respect (before it became purely a George Galloway vehicle) to the Trade Union and Socialist Coalition, these proved utterly underwhelming, achieving little electoral success.

Only now does the left seem to have awoken, with many pledging to support the SNP (running on an anti-austerity platform) or the Greens, currently polling at around 7%. It is hard not to celebrate this phenomenon – there has long been a need for a ‘UKIP of the left’ – designed to push Labour leftwards. And of course, the model of Syriza – a party breaking with the past and winning power through denouncing neo-liberalism and austerity, is immensely attractive. The timing, however, of this shift, is atrocious, and massively counterproductive.

In 2010, Labour elected Ed Miliband, the most leftwing of the credible candidates, after a campaign in which he had pledged not just to accept the dictates of the centre ground, but to actively shape it from the left. The media and establishment fully expected his brother, who had stood on a thinly veiled New Labour continuity platform, to remain victorious, but David’s failure to offer a change of direction change led to the alternative result. Ed Miliband wasted no time in distancing himself from New Labour’s legacy, rejecting the coalition’s austerity narrative in favour of a Keynsian economics that calls on government to stimulate a government out of recession rather than cut spending when it is needed most. During the course of his leadership, Miliband has given speeches that would have been unthinkable during the New Labour era: separating businesses into ‘producers and predators’ – signalling for the first time a break in the post-Thatcher consensus that all private enterprise must be worshipped and celebrated without question. In 2011 Miliband confronted Murdoch – who Blair had given a virtual veto over government policy – demanding his media empire be broken up. It was Miliband’s post-Iraq scepticism over military intervention that effectively stopped Britain and America bombing Syria. And in a range of policies Miliband has moved Labour a huge distance left from where it stood under Blair and Brown: Rent Controls (3 year tenancies as standard), government support for the Living Wage (with tax breaks for companies who implement it), increased taxation on the rich (mansion tax, bank bonus tax, 50p income tax rate over £150,000) a substantial increase in free childcare, repealing the Health and Social Care Act, doubling the length and the value of paternity leave, freezing energy prices and reforming the energy market, cutting tuition fees, and, most importantly of all, allowing a Labour government the leeway to spend £50 Billion more than the Conservatives would in the next parliament, thus preventing the utter destruction of public services that George Osbourne’s spending plan’s imply.

Would the left like Labour to go further? Of course. We’d like to see Living Wage turned into the legal Minimum Wage, railways nationalised, councils given powers to borrow in order to build council houses and more. Miliband hasn’t pledged to do these things (judging that there’s a limit to how much radical change an opposition can pledge to make) , but given the direction of travel he has laid out he certainly would like to, and might well have the opportunity if Labour gains an overall majority. It is true that Miliband has been held back by the caution of others in the party – Ed Balls in particular seems to have blocked radical policies in order to be ‘fiscally responsible’. But in politics, the tone is set by the leader – and Miliband, to those who bother to listen carefully, has made his progressive politics abundantly clear.

And what if Labour loses? What if, because enough of us don’t vote, or vote Green, the Conservatives and Liberal Democrats manage to scramble over the 326 seat line and thus renew the coalition? Will everyone think that this happened because Labour was insufficiently Left wing? The narrative will be precisely the opposite: ‘New Labour used to win elections, but now Labour has swung to the left and lost’. The Blairite fiction will be maintained – that the only way Labour can win is to accept the tenants of neoliberalism and work with the grain of the establishment. We will have lost the best chance we will have for years to install into Downing Street a genuine social democrat who rejects market fundamentalism and believes in the active power of the state to improve society. It will be no socialist new Jerusalem; that would be impossible given where we are today. But we must refuse to make the perfect the enemy of a very substantial improvement: Labour under Ed Miliband is more left wing than it has been for twenty years; now is the wrong moment to abandon it.