An investigation will be launched after the personal information of almost 1,000 Haringey residents was found dumped in an abandoned council building in Crouch End.

The sensitive information, thought to include names, dates of birth, addresses and bank details, mostly relate to housing benefits received by council tenants. The files were found by squatters using the Middle Lane building on Friday, and handed to a national newspaper.

A further 14 files were discovered by the BBC on Monday, while Hornsey and Wood Green MP Lynne Featherstone was being interviewed about the find.

Despite Haringey Coun-cil's assertion that the files relate to cancelled or dormant claims from the Eighties and early Nineties, concerns have been raised about the risks the security breach poses for the 967 individuals whose confidential files have been unearthed.

It is believed the files were overlooked and left in a cupboard when the building - the council's former housing benefits office - was vacated in 2005. For the past six months, squatters have allegedly been using the venue to hold raves.

Haringey Liberal Demo-crat leader, Councillor Neil Williams, said: "This is an absolutely appalling blunder and shows incompetence on a scale that is truly grotesque."

Ms Featherstone said: "Having been aware of this problem since Friday, the council appears to have taken no effective steps to clear this building of confidential information.

"It is clear Haringey Council's concerns were mainly to protect its own back by issuing misleading claims that the information was secured, even though it seems it hadn't checked the building. Protecting the private records of people was a secondary concern. It is scandalous."

An emergency motion tabled by Haringey Liberal Democrats at Monday's full council meeting called for an independent review of the situation. The motion was unanimously passed.

A spokesman for Haringey Council said it will write to those affected.

He added: "The records do not appear to have been tampered with, they still remain complete and intact. The council has secured the files.

"The council very much regrets this has happened. We take the retention of records very seriously and we have procedures in place to ensure records are held securely. It is regrettable that these records were overlooked when this property was vacated.

"The council will be investigating how this happened and will review its procedures to prevent this happening again."