Owen Paterson is a former Environment Secretary and former Secretary of State for Northern Ireland. He is MP for Shropshire North. He is also Chairman of UK2020.

I visited Peterborough on Thursday this week, campaigning with Paul Bristow. He is an excellent candidate – a local business owner with a fine record of charitable service and a determined Brexiteer who wants to see us out of the EU by the 31st October, ideally with a Free Trade Agreement but, if necessary, on WTO terms.

He would be a vast improvement on the previous Labour MP – Fiona Onasanya, a convicted criminal – and infinitely better than the current Labour candidate, who ducked a live hustings on Thursday night.

Under normal circumstances, he would be a shoo-in. But the current Government has made his task unnecessarily hard. The views of those to whom I spoke uniformly echoed the sentiments which saw the Conservative Party lose over 1300 councillors in the local elections and record the worst result in our history – under nine per cent – in the European Parliament elections. These Peterborough voters told me, in effect: the Conservatives said for two years that we would leave the EU on March 29th. We didn’t and we won’t vote for you again until we do. Why should we listen to you on any other subject?

The leadership election will be crucial for the survival of a Party which is now in serious danger of collapse. The current leaderships of both main Parties have missed this point, but the last Westminster voting intention poll from YouGov putting both the Conservatives and Labour on just 19 per cent each should focus the minds of whoever succeeds them.

Conservative MPs now face a binary choice. We can choose to repair the damage wrought by the outgoing leadership by electing a leader with a cast-iron promise that we will leave the EU by October 31st at the latest – ideally with a Free Trade Agreement, but fully prepared to go to WTO terms with pragmatic side agreements already in place.

Or else we can opt for more of the same. More fudge. More prevarication. More delay. If we do, then we should not be surprised when the voters who are currently giving us such a kicking make their permanent political homes elsewhere. The most successful political party of the 20th century – if it survives at all – will look back on a nine per cent vote share as a lofty ambition in the twenty-first

It is, therefore, vital that the current leadership election is conducted in a serious manner and that the leading contenders are properly scrutinised. But with 12 candidates declared – only one short of the number of runners in today’s Derby – we risk looking at best frivolous and at worst utterly self-indulgent. Even on a purely logistical level, imagine how impractical a hustings would be with so many candidates. If every subject were given half an hour, each candidate would have only two and a half minutes to speak and we would have no genuine scrutiny of their ideas.

The 1922 Committee’s Executive needs to ensure that the process is conducted properly. It ought to raise the threshold for being nominated to 12 MPs and see more than one candidate eliminated in each round. That way, we can ensure proper debate among the leading candidates whilst having an efficient election which does not drag on into a lengthy vanity parade.

But some of the candidates, too, ought to take stock. It is very flattering being spoken of as a “potential leader”, receiving emails encouraging one to stand or seeing glowing praise on Twitter, but some must, surely, know that they cannot be considered as genuine contenders. Standing with an eye on a future Cabinet job might seem a clever strategy, but it makes for an unedifying spectacle.

Candidates would do well to adhere to the famous maxim of the Temple of Apollo at Delphi: “Γνῶθι σεαυτόν” – “Know thyself”. Those words were once inscribed on the pronaos of the Temple, and all would pass under them to learn their fate from the Pythia inside. Before trying to enter the holy of holies in Number Ten, all candidates should think long and hard, reflect in the mirror, and put the good of their country and Party ahead of their personal ambitions and vanity.

The threat to the Conservative Party is now existential. We cannot afford to repeat our previous mistakes in another botched leadership contest. We must emerge determined to rebuild the trust which we have lost and the relationship with our supporters which has broken down. We must emerge with a leader unfailingly resolved to lead the UK out of the EU by October 31st, with or without a deal.