Mobile phone users in Teddington have been left without signal after developers started demolishing masts on top of a derelict office block.

Customers of Three and O2 in the area have reported having weaker reception since workers arrived at Somerset House, in Somerset Road.

Phone companies had planned to erect a new mast on the roof of nearby Traherne Lodge, in Sutherland Grove, until angry residents launched a campaign and stalled the project. A spokesman for Three said: “We apologise for any inconvenience the loss of the site at Somerset House has caused for our customers. We are working to resolve this issue as soon as possible.”

Developers have boarded up the former offices at Somerset House as they prepare to convert the building into new homes.

Teddington Councillor Stephen Knight said Three was set to install a replacement phone mast at Traherne Lodge but residents were concerned about the potential health risks.

The leader of Richmond’s Liberal Democrat group said: “I suspect that leaves the phone company in a bit of a mess as they’ve been left with nowhere to put their mast.

“Presumably if the Somerset House mast is down then users are losing reception.

“The trouble is there are not many tall buildings in the area of the right sort of height. I suspect the phone company is now in a rather desperate place, unless they are allowed to build on top of Traherne Lodge.

“If they do so it will not be with the support of the residents.”

He suggested the phone companies could offer Traherne Lodge residents free phone and internet services as compensation for the mast on the roof of their flats.

A spokesman for Ericsson, Three and Everything Everywhere said: “We are working closely with the local council, residents groups and other interested parties to find a solution to this problem as quickly as possible.

“We are hopeful that a solution has been identified and coverage can be fully restored in the near future.”