May has to take back control of Brexit from the hard-liners and the plotters | Simon Jenkins

At last Theresa May will make the speech she should have made a year ago. Her Florence proposals are clearly intended to decontaminate the polluted air round the Brexit talks. She hopes for concord with EU negotiators on a compromise first step towards British departure, on a reasonable timetable. There has to be a deal on this. There has to be a move back from the “cliff-edge” option. But can she deliver?

The first move was always going to be about money. Before anything else the EU is a bureaucracy, and Brexit will mean a loss of around 15% of its budget. From the very start, it was going to fight this with every weapon at its disposal. Britain’s refusal to agree a transitional payment was a total block to progress. May has sensibly removed it.

Britain is clearly accepting reality, to the tune of some £18bn through to the end of the budget cycle in 2021. There are also possible legal obligations on pensions and capital projects after that. The same must apply to the deal on EU residents, which Britain had proposed to handle with typical Home Office administrative hell. “Take back control” should not mean xenophobia and economic self-harm.

The prime minister now offers, in effect, a stay of execution on both issues for a further two years, so that tempers can cool and talks on trade can advance. But she has to clear her political deck of Brexit backwoodsmen. This minority of her MPs, egged on by Boris Johnson, have so far appeared to stymie every movement towards a deal. She has to indicate to them and the country that she is in charge and hard Brexit is just not responsible government. Yes, there has to be withdrawal, but yes there has to be open trade in goods, services and people with the rest of Europe. That should become a technical rather than political matter.

At the heart of May’s problem is her ploy of appointing three Brexiters within her cabinet tent, as her Brexit negotiating “leads”. This has not worked. Two of them, Johnson and David Davis, are angling for her job, which means angling against her and each other. The chief negotiator, Davis, is constantly looking over his shoulder at “cliff-edge” backwoodsmen in his own party, who clearly do not represent polled public opinion, leavers and remainers alike.

If progress is not swift, May has to shift both Davis and Johnson out of the front line and bring the negotiations into Downing Street under her direct control. Such a move has already been indicated by the move of the top Brexit official, Oliver Robbins, into the Cabinet Office. If necessary, make him lead negotiator. Brexit has to be married to reality. It cannot be interred in a Tory party leadership contest. May says she is in charge. Now she must prove it.

• Simon Jenkins is a Guardian columnist