Barnet Council has refunded thousands of drivers who paid £9,000 during a 'free' parking period over Christmas.
Figures published today show 5,200 people paid to park their car during a "poorly advertised" relief period on December 22.
Drivers parted with the cash during the council initiative, intended to boost trade for businesses in the borough.
Barnet Council failed to put notices up in car parks or on off-street signs under the scheme, which was was today labelled a failure by opposition councillors.
The authority revealed the extent of driver's confusion in a written response to a Freedom of Information request submitted by local blogger John Dix.
In total, 1,043 people paid for parking in off-street locations, while 4,186 made pay-by-phone payments in the council’s car parks.
The authority estimated the value of the transactions at £9,000 but revealed today it has already refunded drivers.
Parking portfolio holder Councillor Dean Cohen had offered drivers the chance to park for two hours free of charge on December 22 to encourage shoppers to the borough’s high streets.
But while the council said notices were placed on its website and in the local press, as well as posters in shops, critics say it was not made clear to drivers that they did not need to pay.
Councillor Cohen dismissed calls from the Labour group to introduce a wider free parking period in the run-up to Christmas before proposing his own two-hour relief scheme.
Labour group leader Alison Moore said: “I’m absolutely outraged. To be so dismissive of the Labour group’s suggestions and then not even advertise their own scheme makes a mockery of the whole thing.
“It just shows how badly thought through and executed this was – the cabinet members should be ashamed of themselves.”
Councillor Cohen said he felt the scheme was a success, despite the number of people that paid.
He said: "I was made aware on the day that some people had paid and I immediately instructed them to be refunded.
"We did put up posters but perhaps some more signs should have been put up too. We had a lot more people coming into the town centres as a result of this scheme and there were plenty of people who did not pay for parking."