Longest tunnel in UK is 17 miles and is used by 900,000 people every day

The longest tunnel in the UK might come as a surprise to some. It is actually hidden from sight yet is used by an average of 900,000 people every single day.

The UK has long been known for having some of the world’s most successful and ambitious infastructure. Perhaps most famous is the London Underground. The world famous maze of tunnels connects England’s capital miles underneath the iconic skyline.

Yet one of its lines holds the title of having the longest tunnel in the UK. The Northern Line stretches for an impressive 17 miles and has carried millions of passengers since it opening in 1937.

It’s London’s busiest Tube line, carrying approximately 900,000 passengers every day and transporting more people annually than any other underground line, according to the London Assembly. 

Its tracks go from Morden in the south of the city to East Finchley in the north. The trains make stops at the likes of Bank, Charing Cross and Leicester Square.

However, in just a few years, a new tunnel is set to take the crown from the Northern Line. The Woodsmith Mine Line is currently under construction and will be much longer when it is expected to open in 2030.

It will span 23 miles instead and be used to transport polyhalite, a naturally occuring mineral used as fertiliser, under the North York Moors National Park. The line will stretch from an underground deposit near Whitby to a processing facility in Wilton, near Teesside.

In December, the tunnel passed 30km in length, which is just over 18 miles. The tunnel boring machine (TBM), named Stella Rose, beat the longest continuous drive by a single TBM.

The Woodsmith Mine Line is being built by contractor Strabag for Anglo American. Woodsmith Project director Andrew Johnson recently said: “We are incredibly proud of this milestone.

“The Woodsmith Project is one of the most innovative mining developments in the world today and construction is progressing well.

“We currently employ 1,100 people in the area of which 75% are local – something we are incredibly proud of. We are also proud to have a small international workforce with the specialist expertise we need for this unique world-class engineering project that will provide employment for hundreds of local people for many many years to come.”