The DUP's security spokesman said yesterday he wanted an assurance from the RUC that confidential letters from it concerning personal security arrangements would not again be posted to the wrong person.
Mr Gregory Campbell's call follows the disclosure that a letter from the RUC, intended for the DUP leader, the Rev Ian Paisley, had been posted to a man in Derry.
The letter, containing security information about a leading DUP member under the Key Persons' Protection scheme, was posted to Mr Daniel Bradley in Phillip Street, Pennyburn.
Mr Bradley, a brother of Seamus Bradley, who was shot dead by soldiers in Derry during Operation Motorman in 1972, believed the letter had been deliberately posted to him.
"As soon as I got the letter and read part of it, I re-sealed the envelope and brought the letter up to Strand Road police station," he said.
"It beggars belief how a document of this nature could have been posted to me by the police.
"Why me? I believe the police were trying to use the letter as an excuse to raid and search my home," he said.
Mr Campbell said the security lapse could have had serious consequences.
"There has to be an urgent review by the RUC of their administration. It is obviously a very serious development if security information about a public figure is sent to the wrong person. That is something that has to be revised and reviewed and it must not happen again."
An RUC spokesman said: "The letter did not contain anything of a sensitive nature, and all the parties involved have been informed."