A woman has described how she "nearly passed out" when a cash-strapped council mistakenly paid more than £60,000 into her bank account.
Northamptonshire County Council was meant to pay the money to a holding account before it could be allocated to people receiving child support.
Instead it sent the money to the account of Pat Thornton, 64, along with details of the benefit recipients.
The council apologised and said the data breach had been reported.
Mrs Thornton had been receiving payments from the county council for looking after her grandson, but these stopped when he moved to live elsewhere.
However, in November, she received a six-page letter listing payments totalling £60,963.13 - and details of how this would be broken up for named individuals receiving child support.
When Mrs Thornton checked her bank account, she saw all the money had been sent to her.
"I nearly passed out," she said. "It was unbelievable."
Days later she received a second letter, this time listing payments totalling £749.45.
Again, the money was paid into her bank account.
Mrs Thornton, from Northampton, said: "It was a nightmare."
Eventually she was told to pay back the money by CHAPS - a high-value payment system.
In December, the BBC revealed how the council had to use a credit card to pay a bill of nearly £40,000 for photocopiers after bailiffs arrived at their head office.
Mrs Thornton worked for the county council as a night supervisor, looking after children in care, until she was made redundant in 2007.
She said she had been "panicking" people might not have got their payments.
"I know how awful it is if you don't get money when you really need it," she said.
A county council spokesman said the "human error" was an "isolated incident", and no-one missed out on any money.
"We apologise unreservedly to Mrs Thornton for this error and any distress... caused," he added.
"The data breach has also been reported and due process followed."