We need him to move the Labour Party forward.

Why is Jeremy Corbyn so popular? Here’s a backbench Labour MP, a serial rebel during the Blair/Brown era proclaiming the same ideas he’s spouted for decades and no one has listened to. Now he’s the favorite to win the Labour Party leadership. Even people, like me, who previously supported Blair and Brown, are signing up to his cause.

Some context is needed here. For people outside the U.K., or people who are not natural Labour supporters, it may be difficult to understand the sense of betrayal that Labour Party supporters feel. I have voted Labour since 1987, the year I was first able to vote. I celebrated Blair’s landslide victory and felt that he would genuinely make Britain a better place. I was one of the mugs who initially supported the Iraq war, gullibly believing that Saddam had weapons of mass destruction and that it was imperative to remove his corrupt regime, even without a UN mandate. I thought the light touch that Blair and Brown took with the banks was the right policy; I believed that turning schools into academies would improve standards; I assumed the energy companies were better off as private companies. But, like many people, the fallout from the Iraq War and the aftermath of the 2008 credit crunch has radically changed my views.

Above all, I feel a sickening sense of treachery about the Iraq war every time I watch the news about the Middle East; in so many ways, we caused the tragedy we are seeing now. If Jeremy Corbyn had been leader we wouldn’t have gone to war. We might now be part of the solution, instead of having to shoulder much of the blame for the terrible, bloody mess.

If we had been more like Norway and regulated the banks properly, we wouldn’t find ourselves in such a perilous economic position. A Corbyn government simply wouldn’t have allowed the banks to be so unregulated; I am utterly persuaded that we would be in a better economic position under the leadership of someone who was not in the bankers’ pockets.

As a teacher, I have seen the consequences of Blair’s academies’ program, which has been massively expanded by the Coalition and Tory governments. Billions have been thrown at persuading schools to become independent of their local authorities. Now we find out that not only does the program not raise academic standards but, as a recent National Audit Office report shows, actually nurtures secrecy, poor financial management and, in an ever growing number of cases, corruption. This current government is proposing to introduce regional commissioners to oversee academies, but Corbyn’s simpler idea to bring academies back under local authority control would be more cost-effective and democratic.

U.K. energy companies, it has become obvious, are a cartel, making a profit at our expense and the environment’s. I agree now with Corbyn’s plan to renationalize the energy sector and use taxpayer money to fund a massive drive for more renewables and green energy supplies.

“If your heart is with Corbyn, get a transplant,” Blair said recently — and it totally backfired with his former supporters. To us, Blair has been the one to virtually destroy the Labour Party, not Corbyn. We have utterly lost our trust in Blair and his acolytes, which include the other contenders in the leadership race: Liz Kendall, Yvette Cooper and Andy Burnham. They are all tarred with the brush of the Iraq war, the banking crisis, the academies program, the energy companies’ cartel.

In a witty piece in the Times, Rachel Sylvester compared Corbyn to Bing Bong, the imaginary childhood friend of Riley, the protagonist in Pixar’s animated film “Inside Out.” In the cartoon, 12-year-old Riley’s emotions are depicted as characters who control her mind’s “command module.” At first, Joy is in charge, but a move to San Francisco causes Fear, Disgust and Anger to take over. As a result, Joy gets lost in Imagination Land, where she meets Riley’s imaginary childhood friend Bing Bong, a pink cat-like elephant whose tears are made of sweets. Sylvester’s clever point is that Corbyn — with his anti-Americanism, his ideas about renationalization and printing money to fund public works — is the Bing Bong of the Labour Party. A loved and lost figure resurrected from the past.

This is very true: Corbyn is Bing Bong! This is why we love him. And, to pursue the analogy beyond Sylvester’s piece, who ultimately saves the day in the film but Bing Bong? Like Bing Bong, Corbyn will sacrifice himself to let someone younger take the helm, but he’s the one we need, at this juncture, to give the Labour Party the momentum to move forward.

Most realists don’t expect the Labour Party to win the next election no matter who is in charge; the wipe-out that happened in Scotland, the unfairness of the first-past-the-post system and the conservatism of much of the country make it unlikely that the party has much of a chance for a majority in 2020. But Labour does need to articulate credible arguments against the punitive Tory regime, with its miserable diet of cuts to public services and benefits, xenophobia and tax breaks for the rich. Corbyn is the only person to offer the British public a shift in discourse, where workers’ rights, the necessity for public projects and the environment will take center stage. Hopefully, he can give the Labour Party its heart, soul and, above all, brains back.

Francis Gilbert, a former school teacher, is lecturer in education at the University of London.