St Albans sinkhole: No plans for further sinkhole surveys

A small area of Lower Field, next to Fontmell Close, which will be surveyed, collapsed in 2009

There are no plans to survey any roads other than those immediately affected by the sinkhole which opened up in St Albans, a council has said.

A 33ft (10m) deep hole appeared in the former clay pit site of Fontmell Close in St Albans on 1 October.

A subsequent survey of the road showed a "possible void" which could be three times larger than the existing hole.

But the council said there was no evidence to "suggest other highways in the area are vulnerable".

The authority said the investigation, which included neighbouring Bridle Close, led it to find "evidence of clay pits from which there could have been chalk workings".

But Rob Smith, the deputy director of the environment at Hertfordshire County Council, said: "We know the extent of those clay workings and they are not extensive beyond this bit of the highway."

The council is only responsible for surveying the roads and a "significant anomaly" has shown up (in blue near point A) next to the now filled original collapse (circled)

However, the council did confirm it will survey Lower Field, next to Fontmell Close, where a "small area" collapsed in 2009.

It said it carried out a sub soil investigation and undertook remedial work at the time, but a new survey will be done as the field is a temporary access route for cut-off residents.

Mounds from the council's six-year-old remedial work are still evident - with Fontmell Close in the background

A resident of Sandridge Road, some 200m from the sinkhole, who wished to remain anonymous, said: "We know that clay pits were not always recorded so I would hope they would extend their survey further than just those areas noted as being over the historic pits."

Mr Smith said the council can only survey land it is responsible for and it would be "trespassing if we went off surveying in everybody's gardens".

"If the community could come together to fill in the missing gaps in [our] survey, I think that would help everybody understand the nature of the ground under this part of St Albans," he said.

"We've been happy to share our information about the highway surveys with [residents] to help them better understand what they need to be doing."

A 33ft (10m) deep hole appeared in Fontmell Close in the early hours of 1 October