Clayton Tunnel, the longest tunnel (1¼ miles) on the London to Brighton railway line, begins in Clayton and runs up to 270 feet (82 m) below ground.
The tunnel was built in the 1840s and cost £90,000.
The farmer who owned the land would not grant access to the tunnel unless an edifice was built at its entrance, so the railway company built a castellated entrance around the tunnel.

In 1861 there was a collision at Clayton Tunnel between two trains killing 25 people and injuring 176 others, it was to become known as the Clayton Tunnel rail crash.
Clayton Tunnel, the longest tunnel (1¼ miles) on the London to Brighton railway line, begins in Clayton and runs up to 270 feet (82 m) below ground. The tunnel was built in the 1840s and cost £90,000. The farmer who owned the land would not grant access to the tunnel unless an edifice was built at its entrance, so the railway company built a castellated entrance around the tunnel.
In 1861 there was a collision at Clayton Tunnel between two trains killing 25 people and injuring 176 others, it was to become known as the Clayton Tunnel rail crash.
Clayton, West Sussex