Thousands of Barnet residents charged council tax twice
About 2,500 residents living in Barnet, north London, have been charged twice as much council tax as they should have paid this month.
The council said "human error" was to blame for last Friday's mistake.
Double the usual amount of council tax was taken via direct debit for the first payment of the 2011-12 financial year - on 15 April.
The Tory-run council apologised and said the residents who were overcharged would get their money back on Tuesday.
The council promised to reimburse any costs incurred, such as bank overdraft charges.
Councillor Daniel Thomas, cabinet member for resources said: "One hour after realising this problem we started the process of reimbursing those residents.
"They obviously have my sincere apologies, and we'll make sure there is no financial cost to any residents as a result of this."
Labour leader Councillor Alison Moore said she was "very concerned" by the mistake and blamed "significant" council cuts and staff redundancies.
Last month Barnet Council signed off plans to cut £29.1m, reducing its 2011-12 budget to £255m.
Councillor Moore said the authority was "creaking at the seams".
She added: "Mistakes like this have a very real impact on ordinary council taxpayers.
"The Tories' draconian budget cuts are beginning to bite in service areas across the council."
Charlotte Linacre, of the Taxpayers' Alliance, praised the council for its quick response but warned taxpayers could still be left counting the cost.
She said: "Lots of residents already find the cost of the council surprising but last week some will have had a nasty shock, especially if it stopped other payments or left them with unexpected overdraft charges.
"It's good that the council was quick to start rectifying the mistake and won't leave those affected out of pocket, but taxpayers will still fork out for the admin costs of correcting this error."