Change Britain should lay down their arms and let Theresa May get on with the herculean task ahead of her

We should remember that Change Britain is the same crowd who offered the public the false prospectus of a £350m-a-week boost for the NHS if they voted Leave

The ‘Three Brexiteers’ Theresa May appointed to key posts will give her a recurring headache (PA)

Another day, another challenge to Theresa May’s authority by Europhobes who do not trust her when she delivers her outdated cliché that “Brexit means Brexit”. An all-party group called Change Britain has been set up to keep up the pressure on the Prime Minister. It has been dubbed “Continuity Vote Leave”, as it is backed by many of the key figures in the official Out campaign in the referendum, including Boris Johnson, Michael Gove and the former Chancellor Nigel Lawson.

Officially, the group wants to “work with the Government and with people from across the political spectrum to make a success of Brexit.” Unofficially, its aim is to secure a “hard Brexit,” rather than the “soft” version some Leavers suspect that Ms May wants. Clearly, some Brexiteers cannot forget that the Prime Minister and a majority of her Cabinet backed Remain.

Mr Johnson’s words in a video message backing the new organisation – about the need to deliver “UK control over our laws, borders, money and trade” – were ones Ms May would agree with. Yet his support for the group is symbolic, a reminder that the “Three Brexiteers” Ms May appointed to key posts will give her a recurring headache. In the past week, Downing Street has slapped down the other two, David Davis and Liam Fox, by dismissing their statements as merely their personal views, and the Prime Minister has rejected Johnson’s plan for an Australian-style points system for EU migrants.

The suspicion is that Change Britain is trying to prolong the referendum campaign rather than devote its energies to helping Ms May deliver the brave new post-Brexit world it seeks. True, some Remainers seem in denial about the public’s verdict. Tony Blair is among those to suggest that Brexit might not happen. It would be better for both camps to wait and see what Ms May can negotiate, before Remainers demand a second referendum or Leavers accuse her of backsliding and betrayal.

Understandably, the Prime Minister does not want to provide a “running commentary” on her Brexit negotiations – not least because that would disclose her hand to the remaining 27 EU countries. But the talks will not start until the UK triggers Article 50 of the EU’s Lisbon Treaty, probably early next year. It is clear that the ensuing vacuum will be filled by campaigners on both sides of the debate.

As they argue about whether the UK is heading for a “hard” or “soft” Brexit, attention will focus on the inevitable trade-off between the country’s ability to control EU migration and enjoy continuing access to the European single market. Until we know the shape of the deal, such labels may leave voters cold. Yet the fine detail will matter enormously, with huge implications for jobs and investment.

Brexiteers who fear that Ms May will put a close trading relationship with EU before migration curbs should remember that, as Home Secretary, she took a hard line on immigration and often clashed with David Cameron and George Osborne over their more liberal attitude. She accepts that the June vote was an instruction to deliver tighter control on EU migration and knows she cannot ignore it.

In assessing the Change Britain group, we should remember that this is essentially the same crowd who offered the public the false prospectus of a £350m-a-week boost for the NHS if they voted Leave. Suspiciously, the group appears to have dropped that pledge, even though it surely persuaded some voters to back EU withdrawal. Although Vote Leave insisted that it was a campaign rather than an alternative government, it certainly sprayed promises around as if it were the latter. So we might also be wise to take its continuing pronouncements with more than a pinch of salt.

If the Brexiteers are really serious about “making Brexit work”, the best thing they could do would be to stop fighting the last war, lay down their arms and give the Prime Minister the space she needs to get on with the herculean task ahead.