Homeowners have been left reeling after a developer breached its planning permission by adding an extra floor to “overbearing” buildings backing on to their properties.

Landowner Moat Homes was given the green light in 2010 to build 27 houses and eight flats on land to the rear of Seager Road, Sheerness.

As work progressed last year, Susan Holmes, who lives in neighbouring Barnsley Close, became alarmed at the height of the construction and the number of windows.

She called Swale council’s planning department in July to complain and sent a further seven letters and emails about the development between September and December.

It was not until January 13 that she received confirmation from a senior planning officer that there were a number of differences between the approved scheme and the development on the ground.

The houses, which were supposed to be three storeys, have a fourth level and are 1.6m higher than agreed while the flats are 1.7m too tall. Internal garages are also smaller than expected and a planned cycle storage to the flats has not been built.

The officer said the changes had taken place without any proper consent, prior notice or consultation.

Mrs Holmes, who raised concerns about access, flooding, sewage, loss of rural land, lack of infrastructure and the impact of privacy from the overlooking homes when the original application was submitted in 2010, said: “They didn’t even reply when I made the first complaint. I had to go through stage two to get a reply.”

She added: “It sets a precedent that developers can do what they like.”

Wayne Featherstone, whose garden in Seager Road is directly behind the development, said: “An estate agents has actually said they can’t guarantee selling my house and it’s knocked £40,000 to £50,000 off the value of it.

“OK, we didn’t want them, we fought against them. There were more than 100 people including the academy who were against them and they passed any way.

“But this is totally different. They’ve breached the planning permission. If I as a private person were to change my loft by an inch they would go absolutely mad and tell me to tear it down.”

A sign at the entrance to the building site in Marine Parade says Moat is providing the homes “in partnership” with Swale council and the Homes and Communities Agency, raising questions of a potential conflict of interest given that the local authority will rule on the breach of planning permission.

However, a spokesman for Swale denied this and said it had not been decided yet what action will be taken.

He said some differences had been found with the planning application including an extra floor.

A spokesman for Moat Homes, which is working with developer partner McCullochs, said: “The scheme will provide 35 much-needed affordable homes to the local area.

“A discrepancy has been acknowledged between the planning-approved drawings and current build on-site, which will affect the height of the final scheme.

“The planners and designers are in discussions to understand and address this discrepancy.

“Once a resolution is reached, the planning application will be adjusted to ensure safe, comfortable and locality-appropriate homes which will be vital to regenerating the area and further improving the local community.”