The Brunels' Tunnel by Michael Palin

The significant feature marked by this small building is now no longer easily visible: this is the world’s first major underwater thoroughfare, the Thames Tunnel, commenced in 1825 and finally completed as a pedestrian walkway and underwater shopping arcade in 1843. Sold to the East London Railway in 1865, the tunnel is now part of the London Underground and therefore inaccessible to pedestrians. But take a train to Wapping and the empty shops are faintly visible through the carriage windows, and Brunel's original portico can be seen at Wapping Station.

Sir Marc Brunel and Isambard Kingdom Brunel

Work on the tunnel was supervised by Sir Marc Isambard Brunel with his son I.K. Brunel as Chief Engineer: a cylindrical brick shaft 50ft in diameter was constructed above ground to a height of 42ft at a rate of 1000 bricks per bricklayer per day. The shaft, which can be seen next to the engine house, was then sunk at a rate of 6 inches per day, and once the correct depth was reached tunnelling commenced.

The success of the project was later jeopardised though the inaccuracy of geological data provided, compounded by corner-cutting against Brunel’s protestations on the part of the tunnel’s promotion company. The resulting breach of the tunnel walls by the river caused damage and loss of life on three occasions and in 1828, despite the introduction of a new building material (Portland cement), work was halted and the partially-built tunnel bricked up.

In 1835 the project was revived; conditions were as unpleasant and hazardous as before, with workmen suffering blindness through tunnel sickness and labouring under permanent threat of breaching, or of asphyxiation or explosion through accumulation of marsh gas. These vicissitudes are recalled in the Engine House exhibition and in the tunnel whose superiority of design and workmanship are exemplified in its continuing use as a working railway.

Grand Entrance Hall or Shaft today

The oldest structure in the oldest underground system in the world is now open again after 150 years. A new shelf suspended above the railway separates the tunnels from the upper chamber, which is now a gallery and performance space. The walls, once decorated with frescoes, are encrusted with soot from Victorian steam locomotives, but the line of the original wooden staircase is clearly visible. The steam engines above the Shaft were removed over a hundred years ago, and a herb garden has been planted. On weekends there is a cocktail bar.