The Fifteen Billion Pound Railway: Inside The Elizabeth Line

BBC2, 8pm

Opened to great fanfare last month, the Elizabeth Line (right) is the first new line on the London Underground for more than 40 years and the biggest railway project in Britain since the era of Brunel.

But as the series that has been following the monumental work for a decade returns, we discover that behind the scenes the past few years have been packed with crises and delays. The scale of the ambition is vast, with an army of 75,000 workers involved in the creation of a line that will stretch 73 miles through densely populated urban areas.

As the first of the two episodes begins, the costs are over-running by billions of pounds, and there are more and more monumental engineering and computing problems to be solved if the line is to open as scheduled. ☆☆☆☆★