Alex Deane is Managing Director and Head of Public Affairs UK at FTI Consulting and a former aide to David Cameron. He writes here in a personal capacity.

In the aftermath of the referendum decision, an important question arises: who is to lead the negotiations over Britain’s relationship with the EU? In formal terms, the answer is David Cameron’s successor, of course; but, whilst our negotiator will take direction from the new Prime Minister, whoever he or she may be, plainly in practice that person will not be able to devote him- or herself to the details of the most important negotiations this country will undertake in our lifetimes over the years it will take to carry out. The role will require regular presence in Brussels, remarkable stamina and perseverance, close attention to the minutiae of remarkably wide-ranging regulations, management skills to task and supervise a large and highly skilled team, good political antennae and a willingness and ability to say “no” even at the highest level. Plainly, past experience of senior political office would be a great asset given that skillset.

Presently Oliver Letwin is holding the Brexit brief. Letwin is a very bright man, but has served as the Cabinet Office “fixer” for some time across a range of policy areas – a role in which he will be needed now more than ever. The small unit he presently leads on this topic will have to expand – fast – to scale up to the challenge facing us, and Letwin cannot and should not be expected to ride both horses. Given what I have set out above, I believe that the negotiation requires someone committed to it, at cabinet level, full time. My answer to this question is David Davis.

Having been out of the Cabinet /Shadow Cabinet for some years, and having ruled himself out of the leadership contest, Davis can be viewed as coming to this issue with truly clean hands. In my view, the person undertaking this role has to have been a Leaver who was not involved in the last negotiations to have credibility in it, rather than a Remainer who was active in them. This is true of Davis too. There is a great wellspring of goodwill for him amongst the Conservative grassroots, a group that must feel that their concerns have been listened to and that the person charged with this great responsibility is on the same page as them – Davis does not just satisfy this requirement – he is the only person to truly nail it to the ground.

But this is not just a party question. A true “big beast” with strong name recognition beyond politics and beyond his party, Davis is widely respected in the country – he is a credible player at the highest table. His stance on civil liberties – often in the face of populist press and kneejerk political authoritarianism – showed him to be a man of principle willing to stand up and be counted even when very difficult so to do.

Our negotiator must be well versed in the issues, and anyone who followed his pre-referendum activity will know that this former Europe Minister has thought seriously and deeply about these questions. Furthermore, these negotiations will require real understanding of trade and business. Unlike many other candidates, Davis has had a genuine career of substance in business – including in a FTSE business. He is a credible voice in the city and financial space which so needs reassurance in our present situation.

Finally, he is a remarkably effective politician, as a series of defenestrated Labour Home Secretaries could tell you. These negotiations will be tough. So is DD.

David Davis has been a strong parliamentarian from the backbenches but he should not end his political career without undertaking one more big job for his party and his country. This would be his finest hour.