Another day, another immeasurably tedious row about a government of national unity.

The central and under-reported sticking point is that there is no plausible candidate for the role. Jeremy Corbyn, who leads the largest opposition party, has no hope or prospect of winning a vote of confidence in this House of Commons. There are no circumstances in which former Labour MPs sitting as independents, such as John Woodcock, Ian Austin or Gavin Shuker, will vote to put a man they regard as unfit to be prime minister in No 10.

That view is similarly widespread on the Conservative side. Philip Hammond, who as chancellor of the exchequer sat on the national security council, is said to be particularly vocal in private about the significant influence that a prime minister without a majority has over day-to-day questions of security and foreign policy, while several former Conservative MPs haven’t forgotten that a terrorist attack occurred during the last general election. This group will never endorse Corbyn as a result. There is only one path to a Corbyn-led government: if in the event of a Johnson resignation, he takes office by default, without having to win a confidence vote first.

But Labour is reluctant to concede that the identity of which Labour politician takes office in a hung parliament is up for grabs, and to begin a campaign for Downing Street with a public acknowledgement that some MPs, including former members of his own party, regard him as unfit to hold that office.

What’s left is a row that is primarily about signalling more than anything else. Jo Swinson wants to reassure anti-Corbyn voters that the Liberal Democrats are a safe home for them that won’t result in Corbyn entering office through the back door. Corbyn wants to paint Swinson as a closet Conservative. It’s in both their interests to loudly talk up their respective positions — but the reality is that the people whose preferences will decide if a government of national unity is formed are the independents who sit for neither party; and no amount of cajoling will make them accept a government led by Corbyn.