With just 42 days (and counting) to go before Boris Johnson puts Brexit on the line, the prime minister has to ask himself one question, and one question only: who gave the DUP the right to decide Britain’s future?

It is a question that cries out for an answer. If the Government endorses a Northern Ireland-only Backstop, Britain will almost certainly win support for its exit package at next month’s EU summit. Brussels wants to say yes. Germany and France want to say yes. Ireland is desperate to say yes. The British public, including quite a few Remainers, are ready to say yes, recognising that, in the absence of a second referendum and with Jeremy Corbyn nailing his colours to the fence, the country has to move on and put the last three-and-a-half ghastly years behind us.