All governments are defined by the tensions between the prime minister and chancellor. The rows between Tony Blair and Gordon Brown had such an impact on New Labour that they were nicknamed the “TB-GBs”. Bitter and relentless, they sent a chill down the spine of Whitehall.

The differences between Margaret Thatcher and Nigel Lawson — which culminated in her decision to appoint Sir Alan Walters as her personal economics adviser — led to the chancellor’s resignation and a political crisis from which the prime minister never recovered.

The falling out between John Major and Norman Lamont was so spectacular that the latter denounced the former as leading a government that was “in office but not in power”. Harold Macmillan provoked a walkout by his entire