A fourth suspect was arrested yesterday by detectives investigating allegations that Tottenham Hotspur spied on Olympic officials during its stadium bid.
Scotland Yard confirmed that a 45-year-old man was being held at a south London police station after his property was searched.
The investigation surrounds allegations by West Ham United and the Olympic Park Legacy Company "in respect of the unlawful obtaining of information", the force said.
Three other men, aged 29, 39 and 57, have been arrested in recent months during the inquiry by the Metropolitan Police's Economic and Specialist Crime Command.
Spurs deny putting officials under surveillance.