If Boris Johnson appoints his cabinet on Brexit purity rather than ability, he is asking for trouble

Johnson is poised to name Priti Patel as home secretary, Iain Duncan Smith as chief whip and Geoffrey Cox to an EU ‘negotiating role’ if not Brexit secretary

Boris Johnson is expected to appoint Leave-voting MPs to key cabinet posts if he becomes prime minister on Wednesday. As we report today, he is poised to appoint Priti Patel as home secretary, Iain Duncan Smith as chief whip, and Geoffrey Cox to an EU “negotiating role” if not as Brexit secretary.

While the imminent prime minister’s decision-making is too chaotic for us to say with any degree of certainty that these appointments will be carried through, that they are being considered is an ominous indicator of the nature of the new administration.

It would seem that Mr Johnson, having campaigned for the leadership on the purist Brexit platform of promising what he cannot guarantee – namely to take Britain out of the EU, deal or no deal, on 31 October – is now going to double down by appointing Brexit purists to the top jobs.

Although Sajid Javid may become chancellor and Jeremy Hunt may hold on to his job as foreign secretary, despite both having voted to Remain in the 2016 referendum, it is still possible that Andrea Leadsom could take over the Treasury and another Leaver, such as David Davis, be installed in the Foreign Office.

This is no way to go about cabinet-making. The first priority in any cabinet appointment should be to appoint the best person, based on judgement, ability and experience. The second consideration should be the need to unite the party, parliament and the country at a time of immense challenge.

There is no place for any kind of ideological purity test.

Yet Mr Johnson has already said that any minister in his cabinet would have to accept the possibility of a no-deal Brexit, even though he simultaneously describes it as a “one-in-a-million” chance – and even though parliament has several times made it abundantly clear, as it did again this week, that it will not accept such an outcome.

So to make key cabinet appointments on the basis of how people voted in the referendum three years ago is short-sighted and likely to be counterproductive. In particular, Mr Johnson’s chief whip is going to play a critical role. He or she will need to be trusted by both sides – not just of the House of Commons, as the new prime minister will need Labour votes, but of the Conservative Party, which is even harder to achieve.

Mr Duncan Smith, a hardcore Brexiteer, would be even more disastrously unsuited to that role than he was to the task of leading the Conservative Party 16 years ago.

The same principle applies to other decisions to be taken by the incoming prime minister: it would, for example, be a mistake to require the new governor of the Bank of England to pledge allegiance to the flag of a no-deal Brexit.

The Independent does not expect much of Mr Johnson’s government, but if he really is going to appoint a top team on the basis of Brexit purity rather than ability, he will be heading for trouble even earlier than we expected.