Angled drilling will take place over the next two weeks to explore what lies beneath four anomalies discovered in an initial survey at Fontmell and Bridle Closes, along with one at a nearby playing field used for emergency access.

Acknowledging residents’ wishes for life to return to normal in the cul-de-sacs as soon as possible, a sympathetic Rob Smith, speaking for Herts county council, said: “We understand the anxiety. This isn’t paralysis by surveys – the surveys we have done so far are non-intrusive, where you sweep across the area, and there are areas that need further investigation.

“This is more intrusive, and happens to need a lot more kit and is a lot more expensive, so has to be a lot more targeted.

“Angled drilling is starting next week.”

Cracks in the road surface around the current sinkhole are no cause for concern according to Rob, who said they were present in the first week the cavity appeared, and “haven’t significantly changed”.

Michael Jarrett, speaking on behalf of the county’s highways department, added: “We are monitoring the road levels, including of the concrete poured in the sinkhole, to make sure things aren’t moving still.”

The men added that it was a “priority” for the authority to have the sinkhole and road repairs completed once engineers at Peter Brett Associates had established what remediation was needed, and the best materials for the job, after they received findings of the intrusive investigations.