Jeremy Corbyn’s ascendancy did not, as has been noted, prompt a crisis in the Labour party, rather it highlighted an existing crisis in the party. I believe it also highlighted a crisis about politics in the country as a whole.

While Nick Clegg, Vince Cable and other Liberal Democrat ministers in the 2010 coalition government did manage to get George Osborne and David Cameron to prioritise increases in the tax threshold over reductions in income tax, helping the less well-paid, they could not get agreement to tackle other aspects of inequality, such as the serious shortage of affordable housing.

Someone as candid and straightforward as Corbyn reminded voters who had lost trust in elected politicians of what they wanted their elected representative to be.

But voters also want policies that can be delivered, that will help them in the daily struggle to meet their responsibilities to family and to society. And this is where the divorce between Corbyn and the Labour parliamentary party becomes not only difficult but potentially tragic.

For the past two years politics in Britain has been dominated by bitter debate, often descending to personal abuse, unashamed lies and absurd tribalism.

As a strong supporter of remaining in the European Union, I could not get former Labour ministers to share a platform with Greens or Liberal Democrats, until the final few days of the campaign when the possibility of defeat became plain. Meanwhile, on issues of primary importance to voters, like the future of the famished NHS and the collapse of social care for the elderly and chronically ill, parliament has proved ineffective.

Yet Labour, since its Keir Hardie origins, has been committed to parliamentary democracy. It has always believed, unlike some socialist parties in central and eastern Europe, that MPs are accountable to the people not the party. That is why proposals for parties having the power to deselect MPs, as some around Corbyn have proposed, would be so dangerous.

The challenges to so many of the great social achievements of the Labour, Liberal and Green parties are urgent and immediate. The NHS, adequate pensions, higher environmental standards achieved by the EU and now threatened by Brexit, alongside workers’ rights as the TUC general secretary has argued, could die or disappear in the next few years unless the centre-left parties fight for them instead of fighting one another.

Corbyn spoke movingly in his Guardian interview at the weekend about cooperation. “There is an awful lot we can campaign on together,” he said. He was, I imagine, speaking about the Labour factions. But why not about cooperation between the centre-left parties? These share common values of democracy, social justice, hatred of racism and intolerance, and in most cases want to stay as close to the EU as the referendum result allows – for instance membership of the European single market, support for the European court of human rights (often endorsed by Corbyn), and working together on security, defence and international crime.

I do not think a new party combining the centre-left is likely in the next few years. There are clearly some Corbyn supporters such as the Momentum organisation and some members of the current shadow cabinet who are deeply tribal in their attitude to other parties, and some who dismiss parliamentary democracy with contempt. But allowing ancient prejudices to stand in the way of saving our most precious institutions and rights is unforgiveable. Parties can work together on legislation on which they agree. In some instances, such as the NHS and workers’ rights, the centre-left parties may well command a majority in the House of Commons.

As Nick Clegg has pointed out the country needs an alliance between parties of the centre-left. The Liberal Democrats are already winning local victories, but a working relationship could bring real reforms.

Britain has long recognised the constitutional role of opposition. Corbyn himself holds this essential role. If he is re-elected (this time with the added benefit of thousands of new members now recognised as legitimate voters), he has a duty to help to rebuild trust in politics among young people and keep the best of Labour’s historical legacy.