Three men pleaded guilty on Friday in connection with a spying case involving London's Olympic Stadium.
Police opened an investigation after allegations of wrongdoing were made by West Ham and the Olympic Park Legacy Co. during the bidding to take over the stadium after the 2012 Games.
The OPLC was deciding between bids from West Ham and Premier League rival Tottenham.
The OPLC alleged in 2011 that Tottenham ordered surveillance by private investigators on all 14 members of the board. Tottenham denies any allegations of spying or the illegal obtaining of information.
Howard Hill, a former partner at accountancy firm PKF, was one of the three men to plead guilty at Inner London Crown Court to unlawfully obtaining personal data such as phone bills and bank statements from West Ham and OPLC workers.
PKF was employed by Tottenham for work linked to the stadium bid, but the club has denied being involved in illegal activity.
Hill will be sentenced next month along with Richard Michael Forrest and Lee Stewart.
West Ham initially beat Tottenham to take over the Olympic Stadium but the deal collapsed amid legal challenges Spursand Leyton Orient.
West Ham has since agreed on a new 99-year deal to move from inearby Upton Park and rent the revamped 486 million pound ($781 million) venue starting in 2016.
The 80,000-seat stadium, which hosted the opening and closing ceremonies and the track and field competition at the 2012 London Games, will be downsized to 54,000 seats and reconfigured with a new roof and retractable seats.
As the anchor tenant, West Ham will have primary of use of the stadium, although the venue will retain the running track and stage other sporting events and concerts.
