Boris Johnson. File

David Frost has regained his role as Boris Johnson’s “Mr Brexit”, supplanting Michael Gove, who was previously handling relations with the EU. Officially, Gove, the Cabinet Office minister, is above Frost, a minister of state in Gove’s department with the right to attend meetings of the full cabinet.

But Johnson has decided that Frost’s writ will run on post-Brexit matters rather than Gove’s. There are several reasons why. Frost was chief negotiator during the Brexit talks so there is a strong argument for continuity. Gove does not have enough fingers for his other pies.

While he might be a bit miffed to lose a role overseeing the EU trade deal confirmed only on Monday, he is hardly looking for work. He plays a key role in the response to the coronavirus, and responsible for public services reform and relations with the devolved administrations – a big job with critical Scottish parliament elections coming in May.

Gove is likely to move to a senior post when Johnson reshuffles his cabinet in a few months’ time – perhaps at the Home Office, where Priti Patel’s recent higher profile might not be enough to keep her there, or as health and social care secretary. The man the prime minister calls “Frosty” enjoys Johnson’s full trust.

Although Gove is a pivotal player in his government, Johnson does not feel the same about the Vote Leave ally who backed him for the Tory leadership in 2016 and then wielded the knife by running himself. “I don’t think he will ever trust Michael,” one insider told me.

Frost’s appointment is a signal that Johnson will adopt an aggressive rather than conciliatory approach to EU relations. He is a hard negotiator who made few friends in Brussels during the sometimes bruising talks.

True, the constraints of the pandemic made informal contacts difficult. However, even before it broke out, EU officials described Frost as “not clubbable” and “barely known in EU capitals”, unlike predecessors such as Ivan Rogers and Olly Robbins, who saw such networking as part of the job. Despite Frost’s previous role as chief executive of the Scotch Whisky Association, late-night dinners around Europe are not his style.

In contrast, Gove’s instincts are more consensual. It showed when the UK responded calmly when the European Commission foolishly moved to block vaccine exports from Ireland to Northern Ireland, only to beat a quick retreat. Frost’s approach might have been different. It was his negotiating team that did something equally incendiary during the EU talks, persuading Johnson to threaten to break international law by overriding the same Northern Ireland protocol.

Frost rather than Gove will now be in charge of resolving the real problems the protocol is causing for trade between Great Britain and Northern Ireland, leading to shortages in the province’s shops. Frost is unlikely to enjoy as good a working relationship with his opposite number, the commission vice-president Maros Sefcovic, as Gove does, which could mean trouble ahead on the highly sensitive Northern Ireland front.

Johnson aides offer another reason for Frost’s promotion. As a special adviser he could not issue instructions to civil servants. Arguably there were too many cooks while Brexit responsibilities were split between Gove and Frost, a backroom adviser Johnson appointed as head of a new Downing Street international unit when a Whitehall backlash blocked his previous new job as national security adviser. That appointment raised many eyebrows because Frost has no security experience.

He is now back in his comfort zone, and has taken back control from Gove. The Tory peer will move from shadowy behind-the-scenes operator to front-of-house performer, answering questions in the House of Lords.

Frost’s new brief from 1 March will also include “working on domestic reform and regulation to maximise on the opportunities of Brexit”. Handing that task to a true Vote Leave believer is a sign Johnson is serious about diverging from the EU over time. I’m told we’ll hear more in the Budget on 3 March.

So pro-Europeans who hoped Johnson’s thin trade deal would at least provide a platform on which to build a closer relationship with the EU are going to be disappointed. Despite his rhetoric about working closely with “our European friends and partners”, the current arrangements might prove a high-water mark while the Tories remain in power.