The Thames and Severn Canal is a canal in Gloucestershire in the south of England, which was completed in 1789. It was conceived as part of a canal route from Bristol to London. At its eastern end, it connects to the River Thames at Inglesham Lock near Lechlade, while at its western end, it connects to the Stroudwater Navigation at Wallbridge near Stroud, and thence to the River Severn. It has one short arm (branch), from Siddington to the town of Cirencester. It includes Sapperton Tunnel, which when built was the longest canal tunnel in Britain, and remains the fourth longest. There were always problems with water supply, as no reservoirs were built, while the summit section near the tunnel ran through porous limestone, and there were constant difficulties with leakage.