At the last election, two years and a political era ago, we regretted the drift to the extremes. Today’s manifestos go a lot further. In 2017 Labour was on the left of the European mainstream. Today it would seize 10% of large firms’ equity, to be held in funds paying out mostly to the exchequer rather than to the workers who are meant to be the beneficiaries. It would phase in a four-day week, supposedly with no loss of pay. The list of industries to be nationalised seems only to grow. Drug patents could be forcibly licensed. The bill for a rapid increase in spending would fall on the rich and companies, whose tax burden would go from the lowest in the G7 to the highest. It is an attempt to deal with 21st-century problems using policies that failed in the 20th.

Nor has Mr Corbyn done anything to dampen concerns about his broader worldview. A critic of Western foreign policy and sympathiser with dictators in Iran and Venezuela who oppose it, he blamed Nato for Russia’s invasion of Ukraine in 2014. Last year he suggested samples of a nerve agent used to poison a Russian former spy in Salisbury should be sent to Moscow, so Vladimir Putin could see if it was his.

Under such a prime minister, Britain could not rely on receiving American intelligence. Nor has Mr Corbyn dealt with the anti-Semitism that has taken root in Labour on his watch. Some Remainers might swallow this as the price of a second Brexit referendum, which Mr Corbyn has at last promised. We have long argued for such a vote. Yet Mr Corbyn’s ruinous plans at home and bankrupt views abroad mean that this newspaper cannot support Labour.

The Conservatives, too, have grown scarier since 2017. Mr Johnson has ditched the Brexit deal negotiated by Theresa May and struck a worse one, in effect lopping off Northern Ireland so that Britain can leave the European Union’s customs union. The public are so sick of the whole fiasco that his promise to “get Brexit done” wins votes. But he would do no such thing. After Britain had left the EU early next year, the hard work of negotiating a trade agreement would begin. Mr Johnson says he would do this by the end of 2020 or leave without one. No-deal is thus still on the table — and a real prospect, since getting a deal in less than a year looks hard. There is no good outcome to this nightmare of an election.