There can’t be many theatres in the world where you need to get down on your hands and knees so you can crawl into the auditorium.

But then again, plays aren’t typically performed in railway shafts with London Overground trains whizzing beneath your feet, causing the floor to vibrate.

Inside the Thames Tunnel shaft

It was the first tunnel to be successfully built under a navigable river and the first one to be used for London’s underground railway network. What happened here changed the force on engineering and construction across the world. 
The action took place when the tunnel had been bored halfway under the Thames and there were doubts that the ambitious project would ever be completed. Investors were becoming unhappy and father (Marc) and son (Isambard) were arguing about how to win back their trust.

Set in 1827 on the eve of a celebratory banquet to persuade them it is something they should stick with, the play – only around an hour long and with a very simple set of a table and chairs – was a fascinating insight into a family dynasty.

“To lose confidence in the tunnel is to lose confidence in the Empire,” said an arrogant Marc. But his son thought he wasn’t taking seriously enough the threat of rival engineers being parachuted in to complete the scheme and the two physically fight each other in front of the modern day audience.

The Thames Tunnel was planned to bring a new crossing under the Thames (in the 1820s the nearest place for anyone in Rotherhithe to cross the river was London Bridge, two miles away and expensive to use, as were the watermen who touted for business).

Others before Marc had tried to build a tunnel under the Thames, but they had faced problems with floods and quicksand.

Marc was an accomplished inventor and engineers when he started work on the project, yet he still faced many of the same problems of his predecessors and progress was slow. Work in fact stopped for seven years after a flood in 1828 until he had raised enough money to carry on with the work (it took 18 years in total to finish).

Isambard came onto the scene aged 19 in 1825 as the tunnel’s engineer (the first one resigned after just 18 months of digging). He took a hands on approach to his work and often slept in the shaft, earning respect from the miners who performed their duties in terrible conditions.

But this dedication to the job nearly killed Isambard. He was severely injured in the 1828 flood and was dragged out of the tunnel unconscious. Isambard went to Bristol to recuperate (if it wasn’t for this visit, it is unlikely he would ever have designed neither the wonderful Clifton Suspension Bridge nor worked on the Great Western Railway).

The tunnel was of course completed (I won’t spoil the play by telling you whether father and son resolved their differences), but it wasn’t used for its intended purpose – the roads that would have carried traffic to the entrances were never completed.

Instead, it became a tourist attraction, bringing in a million visitors in the first month that it opened in 1843. Queen Victoria even visited later that year. Fairs and banquets were held and it was the place to be seen.

Music was played, refreshments were offered and souvenirs traded, with an American novelist describing “an arched corridor of apparently interminable length, all along the extent of this corridor, in little alcoves, there are stalls or shops, kept principally by women, who, as you approach are seen through the dusk offering for sale views of the Tunnel, put up with little magnifying glass, in cases of Derbyshire spar; also cheap jewelry and multifarious trumpery”.

The novelty did however wear off with visitors and in 1865 it was sold to the East London Railway for £200,000 and in 1869 the first trains travelled through the tunnel. The line running through it now forms part of the London Overground network and the Rotherhithe shaft is managed by the Brunel Museum (first opened in 1980).

This left the entrance – which until recently when a £250,000 concrete floor was installed it was inaccessible – redundant

Plans are in place to modify access to the shaft so that visitors no longer have to enter on all fours and descend down a scaffolding staircase (Marc in the play amusing referred to the present by jokingly complaining about a “makeshift staircase”) to enter the shaft. This will make it possible to use the attraction for many more events (it took quite a long time to clear the auditorium at the end of the play).

The “theatre” entrance

After the play I travelled north on the London Overground and given the performance I had just seen it seemed very special to travel immediately through Brunel’s darkened tunnel.

I tried to imagine what it would have been like today if a road had run through it. And then the I thought of the glamour of when it was a tourist attraction. 

But then I considered how great it is that the tunnel still has important role in ferrying people around London (and acting as a different sort of venue for theatre-goers). Let’s hope completing the renovation work doesn’t take another 18 years!

The Eight Wonder of The World closes on Sunday. More details here.