A planned 3,500-home new town off the A417 in Gloucestershire is in a “high risk” gas zone above a key high pressure pipeline, according to the UK’s gas network operator.

The National Gas Transmission has warned Forest of Dean District Council (FoDDC) that the possible new town near the Ledbury junction of the M50 “has been found to be within the High Risk zone from National Gas Transmission plc’s apparatus”.

The letter, sent on April 8, adds that the Glynchbrook development “must not proceed without further assessment from asset protection”.

Maps attached to the letter seen by Gloucestershire Live show a high pressure pipeline running through the heart of the proposed Glynchbrook site in Redmarley.

Residents have expressed their fear and anger that the new town would be in a “high risk” gas zone, adding that they should have been informed about it before the end of the public consultation into the council’s housing plans.

Vicky Goodall, 52, a nurse from Redmarley, said: “I’m really worried about this gas pipeline and I wish the council were upfront about this earlier.

“One wrong move by excavators and it’ll be a massive problem. The council must understand how concerned the people of the Forest of Dean are about Glynchbrook. We know how badly the site floods, it won’t have a trainline, it’ll ruin the Malvern Hills – and now we find out it’s in a high-risk zone because of the high pressure gas pipeline.”

Her fears were shared by fellow local resident Rob Whitestone, who works in the motor industry, who pointed out that the Labour MP for the Forest of Dean Matt Bishop had publicly condemned the Glynchbrook plan on the grounds that local infrastructure would not be able to cope with 3,500 homes.

The 42-year-old said: “The damage this housing development has done to trust in local government is incredible. I’ve never known anything like it.

“Why weren’t local people told that Glynchbrook – along with all the other issues – was in a high risk area because of this gas pipeline?

“The local MP is doing the right thing – he wants new houses, but not at the expense of our landscape and not in places where the infrastructure can’t cope. Here’s hoping the council takes his lead and comes to its senses.”

John Heap, 74, from neighbouring Eldersfield, feared that mitigating the risks associated with the gas pipeline would be very costly.

He said: “How expensive is it going to be to build around a high risk gas pipeline? There will have to be loads of redesigns, approvals and safety work. It surely means the Glynchbrook site becomes more costly and therefore even less appealing.

“Just when you think there can’t be anything else wrong with Glynchbrook, we’ve found it’s on top of a high-pressure gas pipeline. You couldn’t make it up!”

A spokesperson for Forest of Dean District Council said they are aware of the National Gas Transmission letter and it will be considered as part of the ongoing review of technical evidence.

“Councillors will continue to assess all evidence alongside public feedback received during consultation,” a spokesperson said.