Three decades ago, the UK and French governments were close to a new Entente Cordiale. The previous year, 1984, both had agreed to invite private developers to submit proposals – to construct and operate a fixed cross-Channel link. Provided it could be done without any public money.

That historic pact green-lit the eventual £4.65bn Tunnel, opened in 1994, now carrying 50,000 passengers and 54,000t of freight a day. Yet readers, whose memories stretch a little further back than 1984, may recall a previous attempt 10 years earlier to connect France and Britain. That began in November 1973: the two countries signed a treaty, intending to finance the undersea project with government-guaranteed loans. But, just over a year later, the scheme was abandoned when the UK’s new Labour government pulled out, claiming it no longer wanted to finance the project.

By that stage, a consortium known as Cross Channel Contractors had been awarded the contract to build it. They’d already commissioned two tunnel boring machines (TBMs) to begin excavating a service tunnel which would run between the two proposed tunnels. Robbins, from America, built a TBM to dig from the French side, while Gravesend-based Robert L. Priestley made one for the British end. Both machines had been manufactured and delivered by the time the project was cancelled.