On the day after 7 May, having personally seen five years of hard work pay off and my majority nearly tripled, my wife and I sat down and did what a lot of Labour people did – we cried. And I don’t mean tear-strolling down the eye crying, I mean real crying. You would have though we’d spent election night watching Beaches on DVD.

And the thing that got me most of all was this: having been born under Thatcher, I lived my entire childhood under the Tories. Now, because of the scale of our defeat my own children will have exactly the same experience. The visible signs of modern Conservatism – food banks, homelessness, and in-work poverty, will become reference points of their childhood.

Over the weekend some party members have been tweeting MPs asking them to nominate Jeremy Corbyn to ensure the leadership contest is a full ‘debate’. I upset a few of them by saying I thought it was the actually the job of MPs to put forward a list of credible Party leaders to the membership. Because I upset them so much, I thought I’d elaborate my argument on here.

Let me say a few incontrovertible truths before I go on. It is undeniable that Jeremy Corbyn is a lovely man. It is also undeniable that a decent chunk of people think the latter years of the Blair and Brown governments lost their way, and were no longer convinced that the Party was pursuing it’s historic mission to build a fairer society (this may be harsh given the financial crisis, but it remains how they feel). It’s also undeniable that we need these disillusioned people to vote Labour as much as we need to attract people who just voted Tory.

However, if people think Jeremy is genuinely the man to win a parliamentary majority, a leader who can win not just Nuneaton but also Corby and Thurrock, then they are deluding themselves and someone needs to say that. If Jeremy was leader the Tories would win a majority of at least a 100, and possibly more. It would be comparable to the Tories selecting Bill Cash as their leader. Nor is it a given that his presence in the contest will improve the debate – much like primaries in US politics, it is far more likely it will pervert the centre of gravity even further from where the public are. One candidate has already described the 2015 manifesto, which has put the Tories in power for a decade and made the break up of the UK look likely, as the best they’ve ever stood on.

The charge put against people like me is that we just want to win at all costs, or are happy to become a watered-down version of the Tories. On that point they are even more wrong. I desperately want a Government that starts to make the UK the sort of prosperous and compassionate country which many other European nations have already achieved. I desperately want a Government committed to reducing inequality, that brings in a living wage and ends zero-hours contracts. I want a Government that has at its heart a modern industrial policy, that spreads good employment more evenly around the UK. I want a Government that takes climate change seriously, and ends the UK’s mistaken view that the only way to intervene abroad is to fire off a few missiles as a show of strength. I’d even like to change the UK’s absurd electoral system, ending the unhealthy obsession with a handful of swing voters in marginal seats. And you know what? All of this is entirely possible, but it requires us to at least try and win rather than spend a few months making ourselves feel good about losing.

To do it means acknowledging that business isn’t our enemy, it’s actually our ally if we want full employment and better jobs. It means recognising that we could have universal childcare, if only we didn’t spend so much money on debt interest. And it means understanding why so many Labour voters love the NHS, but abhor a benefits system which they believe gives them very little for what they put in.

We can have a Labour Government we can all be proud of, but it means we need to accept the world as it is, not how we’d like it to be. But most of all, it requires us to start taking ourselves, and this leadership contest, more seriously. Because if we don’t, no-one else will.

Jonathan Reynolds is the Lab/Co-op MP for Stalybridge and Hyde, and Shadow Minister for Energy and Climate Change