WORKERS restoring a stretch of the Kennet and Avon Canal have discovered an historic piece of engineering thought to be the last remaining example of its kind.

A team carrying out re-lining work between Bradford on Avon and Dundas Aqueduct found a 200-year-old gate in the bottom the drained section at Limpley Stoke, which was designed to shut off the section in case of leaks.

Project manager John Laverick, of the Kennet and Avon Canal Partnership, said the heritage find is thought to be unique.

He said: "They were known about in the canal's 200-year history but the last one was thought to have been destroyed. Nobody knew it was there. We have found our very own Mary Rose in the mud."

The gates were included in the canal design as a way of blocking off sections of the canal to prevent all the canal water gushing through leaks it was feared may form in areas of geological concern. They were designed to lie flat on the bottom of the canal until needed.

Mr Laverick said: "In terms of our £25m lottery grant, heritage is a big issue. This is a 200-year-old artefact discovered as it was engineered at Limpley Stoke. It is pretty unique.

"It is still in relatively good condition and would have been pulled into position with a rope through a pulley block and a horse on the towpath."

The work is part of a £29m, five-year programme of improvements to the canal which are being overseen by the Kennet and Avon Canal Partnership.

Work on the 2.5km Bath section between Claverton and Bathampton was listed in the top 20 construction achievements out of 180 at the British Construction Industry Awards.

Mr Laverick said: "A major element of the restoration of the Kennet and Avon Canal is extremely specialist relining work in the Bath Valley section.

"We have a team of working on the enormous five-year project from civil engineers, land surveyors and architects to ecologists and archaeologists."

The work has temporarily been hit by the weather, but Mr Laverick said it should still be completed in time for the waterway to be re-opened next spring.