The Sheffield and South Yorkshire Navigation has been closed at Rotherham following the collapse of a wall.
A large section of wall, understood to be part of the old Beatson Clark glass works, has collapsed - partly into the canal - about a quarter of a mile north of Rotherham Lock.
A further section of wall is in danger of collapse.
The canal will remain closed until the wall has been stabilised and debris removed.
Update
(31st July):
The debris in the canal from the wall has now been buoyed off. Half of the channel is now navigable to a depth of 1.8 metres. Boats should keep to the side away from the buoyed area.
Any enquiries regarding this stoppage should be made to BW on 0113 281 6860.