Howard Hill, a former partner at accountancy firm PKF, was alleged to have employed private investigators to get information on the Premier League club and the Olympic Park Legacy Company (OPLC) while Tottenham Hotspur were bidding for the site.

Tottenham used PKF to carry out an investigation linked to their bid, but have always denied any involvement in the illegal activity which included obtaining phone bills and bank statements.

Among those targeted was Karren Brady, the vice-chairman of West Ham United who appears on BBC programme The Apprentice as an aide to Alan Sugar, a former chairman of Tottenham.

West Ham United vice-chairman and The Apprentice star Karren Brady was among those who had their personal data targeted by consultants working for Tottenham Hotspur

At Inner London Crown Court, Hill, 59, from Stockport in Greater Manchester, pleaded guilty to obtaining personal data contrary to the Data Protection Act 1998.

Fellow defendants, Richard Michael Forrest, 31, from Crawley, West Sussex, and Lee Stewart, 40, from Esher in Surrey, admitted the same charge, Scotland Yard said.

Three counts of fraud by false representation involving the defendants were left to lie on file.

The three men will be sentenced on December 20, Scotland Yard said.

The information they obtained were alleged to have formed the basis of a story that appeared in The Sunday Times in June 2011 that made a series of allegations about West Ham's behaviour during the bidding process, including that an OPLC director had been paid by the club for consultancy work.

They were charged in November last year by detectives investigating claims made by West Ham United and the OPLC.

A total of six people were arrested throughout the course of the investigation.