THERE were two ferries working the river crossing at Woolwich. They loaded up with cars and lorries, one on either side of the Thames. Then they backed out, turned around, circled each other at a distance and docked at the other side.

Down below the riverbed I was crossing on foot. I descended in a wooden lift. The liftman said nothing. The doors opened into a long narrow tunnel lined with white tiles and poorly lit.

The tunnel sloped down to the middle and then climbed back up to the other end. There were other people in the tunnel. Except for our footsteps we crossed in silence, surveyed by the liftmen and their closed-circuit cameras. They can see who is in the tunnel and go down to meet them. Somebody said 'Thank you' to the second liftman. I went back across the Thames on the ferry.

The digging of the tunnel was begun in 1876 after nine men drowned on a foggy morning while crossing the river to work in a boat. These days people use it to get to Safeway or the art college. It is 1,655 feet in length and 69 feet 3 inches below the high-water mark.

There is another foot tunnel upriver at Greenwich, where people emerge to see the Cutty Sark and Francis Chichester's Gipsy Moth IV. At Greenwich the lifthouses have pleasant glass- domed roofs to let the light in. At Woolwich they do not.

Woolwich foot tunnel is at Ordnance Survey grid reference TQ 4379.

(Photograph omitted)