Misgivings about building homes above a deep historic clay pit – later the site of St Albans’ massive sinkhole – were raised over 40 years ago, a Herts Advertiser investigation has revealed.

Herts Advertiser: A car is trapped on its driveway by the sinkholeA car is trapped on its driveway by the sinkhole (Image: Archant)

Alarm bells were ringing at one stage when Herts county council realised, according to a confidential letter, that some homes in Bridle Close were built on land of which it owned the freehold, without its approval.

The revelations are contained in the archives of the former St Albans city council, which are now held by the current district council.

They show records of letters, planning applications, residents’ objections and official documents relating to Fontmell Close, where a sinkhole opened up in the road on October 1, and Bridle Close, which runs off it.

From the early 1970s, the closes were built in several phases off Seymour Road from the back gardens of homes along Sandridge Road.

Records show the county was concerned about “abnormal site development” in a confidential letter sent to the city council in October 1977.

It said: “It has recently been discovered that part of the residential development at Bridle Close has been constructed on land which is in the council’s freehold ownership.

“The county council received no notice that development was intended on this land and no approach was made by the builders…with a view of acquiring it.

“I understand that the land taken from the county council’s site was infilled and compacted and that the properties erected thereon had to be constructed on pile foundations with reinforced beams.

“If you could give me more precise details of the infilling and of the foundations provided for each of the properties constructed wholly or partly on the county council’s land, I would be most grateful.”

There were also concerns about the water table, with a 1973 memo to a city engineer from the manager of parks and recreation about the former deep clay pit explaining, “The pit seems to have been an old chalk working. It is strictly of local interest only, as one would have to be very close indeed to realise that it is there.”

The officer warned, however, that if the pit was filled further, trees inside it would die, and the water table would be ‘altered’.

County council officials also warned against over-development of the site, particularly in the third phase of construction, at what is now Bridle Close.

A letter from the city council’s engineer and surveyor said land sold to developers by building yard operator Mr Tant “embraces a very deep pit, part of which is on the site in question, and part of the adjoining land owned by the Herts county council, which is to be developed for primary school purposes.

“The development of this site will require the provision of piled foundations [as] has been necessary in certain cases when the applicants developed Fontmell Close.”

While there was pressure applied by developers on the city council to approve applications to expand from the late 1960s, neighbouring Sandridge Road residents objected to the loss of green space and said the site would become an eyesore and a ‘debased area’.

But that did not deter builders HJ Brosnan Ltd, of Potters Bar, which won approval for the second phase to extend Fontmell in 1973, and the third phase, for Bridle Close, in 1975.

• Power, gas, water, sewerage and telephone services have now been restored to most homes in Fontmell Close. Results of the county council’s survey of the sinkhole have not yet been released. Residents have contacted the Herts Advertiser to express their gratitude to the many people who have provided support since the incident.