The PAYE online filing service was suspended last night after complaints from accountants that they could inadvertently gain access to details of other PAYE clients including the Metropolitan Police.

The problem, which led HM Revenue and Customs to suspend the service until this morning, related to 'P9' supplementary coding. Name and staff numbers of client employees could be viewed by other accountants using the system.

'I tried to use the secure mailing system, and called up someone else's mail,' one accountant told Accountancy Age.

'We are investigating this with urgency,' said an HMRC spokesman.