The Caen Hill flight of locks near Devizes will remain closed until at least tomorrow (Friday) after a narrowboat sank in a freak accident.
Officials at the Canal and River Trust and owners Bath Narrowboats are trying to work out how the Lady Victoria sank while negotiating Lock 22 at Lower Foxhangers, near Devizes, at around 6.30pm last night.
The owner of Bath Narrowboats, Lionel Meaden, said: "Normally what happens in incidents like this is that the rear of the boat catches on the sill of the lock gate and it rises while the bow is falling.
"But in this case the opposite has happened. The front rose with the water level but the rear didn't, the boat filled with water and sank. The poor chap on board had 30 seconds to get off.
"The people who hired the boat, from High Littleton, are experienced boaters and they are at a loss to explain what happened."
Workers from the Canal and River Trust, which recently replaced British Waterways as custodians of the country's waterways, said that they will drain the lock and the boat, put in a coffer dam and then refloat the Lady Victoria.
But it is not likely to happen until late tomorrow or even Saturday and until then the lock flight is unnavigable.