A parody of a debate: that’s been the story of the Labour leadership contest to date. A debate is supposed to involve some diversity of opinion. If it is reduced to quibbling over nuance and tone, then personality becomes a substitute for clarity. Genuine political debates are good for democracy, because they force each candidate to define their views clearly and avoid relying on platitudes. With the current leadership candidates dancing inelegantly on the head of a pin, we have learned little – other than just how uninspiring, stale and vacuous a party leadership contest can be.

That’s why Jeremy Corbyn’s entry into the Labour leadership race is so important. Disclaimer: I’ve known Jeremy for years, and have shared numerous platforms with him on issues ranging from peace to social justice. He is the very antithesis of the negative caricature of an MP: he’s defined by his principles and beliefs, uninterested in personal self-advancement, and determined to use his platform to further the interests of people and causes that are otherwise ignored.

He’s one of the most likable MPs – and a five-time winner of parliamentary Beard of the Year

A proponent of peace, a staunch internationalist (he was protesting against Saddam Hussein when the west was arming him), a fervent believer in workers’ rights, and an opponent of austerity whoever peddles it, Corbyn would inject the substance so disastrously missing from the current contest. He’s also one of the most likable MPs – and five-time winner of parliamentary Beard of the Year, which must count for something.

It is up to Labour MPs whether party members and trade unionists will have the opportunity to have a meaningful debate. Under Ed Miliband’s leadership the threshold for how many nominations a leadership candidate must receive to appear on the ballot paper was raised to 15%. Unless 35 Labour MPs nominate Corbyn, this farce of a leadership contest will continue and the Labour party – and the country as a whole – will learn nothing from it.

Back in 2007, I worked for the prospective Labour leadership campaign of John McDonnell, a close ally of Corbyn. But after McDonnell outshone Gordon Brown in a single leadership hustings – with the soon-to-be-unopposed leader becoming evidently flustered during the course of the evening – the Brownite goons roared into action. They knew their man would win, but they feared an unexpectedly positive showing by McDonnell in both the debates and the final result. Arm-twisting and arm-breaking followed, and a coronation ensued. Brown never defined himself, and arguably fatally wounded his premiership from the outset.

More than one candidate is guaranteed to make the leadership election this time around, but with so much agreement on the key issues confronting the country, the consequences will surely be the same. According to the polls, millions of Britons support a living wage, a radical housebuilding programme, public ownership of utilities and services and higher taxes on the rich. Many of them voted for Ukip, the Greens or the SNP. Yes, many of them may lack confidence in the ability of politicians to deliver such policies. But given their widespread backing, these policies surely at least need a hearing in the leadership contest of the dominant,purportedly left-of-centre party in Britain.

Corbyn was an arch critic of New Labour, and ironically would be the sole real defender of New Labour’s record in the contest. He would fight a rearguard offensive against the lie that Blair and Brown caused the crisis by spending too much money on schools and hospitals – spending backed, penny for penny, by the Tories until the end of 2008. He will be able to draw from the findings of Britain’s leading pollster, John Curtice – who accurately predicted the outcome of the election; these findings dispute that Labour lost for being too leftwing, and underline that Labour lost Scotland partly for being too rightwing.

Corbyn could also draw on the conclusion of Peter Kellner, the YouGov pollster, that however Ed Miliband allowed himself to be portrayed, his policies were less radical than those of Tony Blair in 1997. He could nail why Labour lost: the implosion in Scotland, and the consequent anti-SNP hysteria; the lie of “overspending”; and the lack of any coherent alternative.

If Labour MPs deny the party and the country a genuine debate, it will reflect disastrously on them. It will do whoever emerges victorious no good, either. Labour has just suffered one of the worst defeats in its history. If the party doesn’t have the good sense to have a meaningful debate now, you might wonder why it doesn’t just pack up. So come on, Labour MPs. Put your future careers aside for party and national interest. Lend Corbyn a nomination, and let a real debate begin.