The scene after the Brecon and Monmouthshire canal burst

Eight people were rescued and a road was closed after the canal breached in Gilwern, Abergavenny, last month.

A section of the historic waterway from Llanover to Llangynidir will be closed for a month to allow inspectors to check its bed and walls.

British Waterways said initial checks suggested erosion caused the breach.

The towpath along the canal will remain open while the inspection work is carried out and British Waterways is working with hire boat operators and private boat owners to move their vessels to either side of the area affected.

'Absolute confidence'

Julie Sharman, general manager of British Waterways Wales and Border Counties, said: "Our initial investigations into the cause of the breach at Gilwern indicate that the canal embankment may have been undermined by internal erosion.

There was a landslide after part of the canal burst its bank

"Despite having a thorough inspection regime, and extensive geological information, a failure of this type was not expected.

"In light of this we have taken the view that the only way that we can give local people absolute confidence in the safety of the waterway, and ensure its long-term integrity, is to carry out a complete geo-technical assessment.

"We clearly regret the disruption that this will cause and would like to thank our partners and the local community for their support and understanding.

She added: "British Waterways is committed to securing the long-term future of this beautiful, historic canal which plays such an important role in the life and economy of south Wales."

A group of homes were evacuated in Gilwern after the alarm was raised about the canal breach on Tuesday, 16 October.

Three were so badly damaged by the torrent of mud and water that two families were evacuated to Gilwern Community Centre.

The A4077 was closed between Crickhowell and Gilwern for about a week following the breach.

Twenty-three hire boats were also affected, with cranes brought in to help right them.