LETTERS that should have been delivered up to two years ago are at last dropping on doormats, following a major investigation into missing mail.

Royal Mail bosses in Darlington revealed that they had discovered a stash of undelivered letters.

But they declined to comment on rumours that the mail was found in the possession of a postal worker.

Bewildered residents have contacted The Northern Echo in recent weeks to say they have been getting post dating back as far as 2002.

They include pensioner Margaret Nayman, who was amazed to receive a building society cheque dated May 24, 2002.

Royal Mail, which initially said it could not speculate on the cause of the delay, confirmed last night that missing mail had been discovered and was being belatedly sent out.

A spokeswoman said: "There has been an internal investigation in the Darlington area, as a result of which undelivered mail has been recovered.

"That mail, some of which does date back two years, is being delivered with a note of explanation and apology."

She refused to say how much mail was involved or whether any action was being taken against an employee.

Tom Clark, North-East delivery representative for the Communication Workers' Union, said he was unaware of the inquiry.

But he added: "If Royal Mail finds post like this, they will always deliver it."

A fortnight ago, Royal Mail came under fire for failing to meet all 15 of its performance targets for the first quarter of the financial year, although bosses said there was "real evidence" the service was improving.