After 25 years in business, Eurotunnel is at a junction, with many of its staff facing retirement and new recruits being drafted in. And the next batch of wannabe shuttle drivers has just arrived for the first round of testing. The tests, however, are ruthless, with a 90% fail rate, so who will make it through?

Meanwhile the passenger comings and goings never stop and the summer is the busiest time of all, with super cars arriving in convoy for the Le Mans 24 hour race. But as the French step up their passport controls, and the screens jam at the Terminal Control Centre, will the supercars make it to France on time?

We also find out how the teams cope with “no tarmac day”, the busiest day of the year, when the schools break up and 10,200 cars head for the tunnel. Then we take a rollercoaster ride through the tunnel with train drivers Tash and Steve, who show us why the undersea geology makes the tunnel bend.

Inside the world’s biggest train shed in Calais, we see how maintenance teams keep the locomotives running. Back in Folkestone, we meet the UK team hard at work in the slightly smaller UK shed. Why do they love sheds? How come they don’t want to retire? And why is it that some of the staff are more concerned with Pexit than Brexit? Show less