More than 100 homes on the Sonora Fields estate have been slapped with an unexpected increase in their council tax bill following an error.

Letters from Swale council were sent to residents towards the end of last week informing them they will pay an extra £19.82 for a Band D property for the financial year 2015/16.

It came almost two months after households received the initial invoice for the amount they would pay for the year.

The areas affected are Gemstone Court (20 homes), Opal House (12), Quartz Way (18), Spinel Close (nine), Peridot Walk (11), Pearl Walk (16), and Helidor Walk (22) and Garnet House (six).

A spokesman for the local authority said: “The finance team are the payment authority for council tax on behalf of parish, town, borough and county councils, as well as local police and fire services.

“When these homes were built, council tax were incorrectly informed that the properties were part of the un-parished area of Sittingbourne, rather than the Bobbing Parish Council area.

“Upon discovering this, the parish council brought it to our attention, and so the precept payable to them to provide local services – £19.82 a year for a Band D property – has been added to the council tax charges of the properties affected for the new financial year.

“As the error was only pointed out to us relatively recently, we were unable to take the first installment from people’s council tax bills in April.

“This was therefore added to the May bills, and subsequent payments will be at the usual rate.”