More cracks have appeared in the St Albans cul-de-sac since a 20-metre-wide sinkhole dramatically swallowed a chunk of road over a historic clay pit.

The Herts Advertiser has returned to Fontmell Close, where the cavity materialised on October 1, to photograph the sinkhole since it has had 48 lorry loads of foamed concrete pumped in by engineers.

Further cracks have appeared around the hole in the road, and photos taken of a house nearby reveal cracks in paving close to a brick wall which has partially collapsed into the cavity.

The hole was filled with 535 cubic metres of special concrete to within one metre below the road surface by the end of last Tuesday (7).

Experts are still monitoring the site, using specialist equipment to test for any movement. But the analysis of these tests will not be known until the end of this week at the earliest.

A spokeswoman for Herts county council said that a micro gravity survey is being done to detect anomalies, such as cavities, under the road.

Costs so far to deal with the emergency response and initial repairs are estimated to be around £100,000.

However, the council is not sure whether other technical work may still need to be carried out.

The spokeswoman added: “Our response so far has been about safety, ensuring local residents are cared for, and dealing with the sinkhole itself.”

Residents have been advised that if they are concerned about anything, to let one of the local authorities know, and it they notice any cracking in their buildings or damage in their garden, to contact their home insurers.

If they are concerned that a building may be structurally unsound, they should contact the district council’s building control team straight away.

Those worried about further sinkholes opening up in the highway or footpath near their home should report them to the county council.

A major incident was declared upon the appearance of the sinkhole, which knocked out water, power and sanitation services – affecting more than 50 homes.

Two weeks on, 44 families have returned to their homes as power, water, sewerage and telephone services have been restored. However there is still no gas supply.

National Grid is awaiting the go-ahead so they can do the necessary work as soon as possible.

Among those waiting to return home is Julie Langford, of Fontmell Close, whose family has to remain in a hotel because without gas, there is no hot water or heating.

Officers from both local authorities, along with representatives of National Grid, Affinity Water, BT Open Reach, Herts Police, Herts Fire and Rescue and Citizens Advice met with about 50 residents last Friday (9) to discuss and update those affected by the incident.

St Albans MP Anne Main has paid tribute to the “efforts of the emergency services that attended this dramatic event. It’s a blessing nobody was hurt.

“By ensuring that safety measures were put in place as soon as possible they without doubt prevented the possibility of further risk to residents.”