The Ombudsman is to investigate allegations that the Office of the Information Commissioner withheld key paragraphs from an Abbey National letter acknowledging that procedures were not followed, after Johnson requested the document using his rights under the Data Protection Act.
Johnson, who is suing Abbey National over the affair, claimed in documents lodged with the Ombudsman that he was forced to launch judicial proceedings against the information commissioner to obtain the full copy of the letter.
The missing paragraphs showed that Abbey National had made changes to its procedures to ensure that the events that led to the bank posting warnings about Johnson and his wife on the Cifas fraud database could not happen again.
"Unfortunately, in Mr Johnson's case the procedure was not followed. If it had been, it would have prevented the Cifas entry against Mr Johnson from being made," the bank said in its letter.
Johnson has alleged in court documents that processing errors by Abbey National led to him being sacked from top IT roles in the IT departments at Deutsche Bank, UBS and Perot Systems, rendering him virtually unemployable in the industry.
Abbey National and Johnson declined to comment.
The Information Commissioner said, "We have gone to considerable trouble to handle this case properly, and we hope the Ombudsman will reach the same conclusion