The bitterness of the battle for the £486 million Olympic Stadium was publicly laid bare for the first time on Tuesday.
Baroness Ford, chairman of the Olympic Park Legacy Company (OPLC), which is in charge of securing a viable economic future for the home of the London 2012 Games, told the London Assembly: "The thing that I have learned in the last 12 months is that there has been all kinds of behaviour.
"There has been legal challenges and people have stood behind it anonymously - all kinds of things have happened. My board were put under surveillance by Tottenham Hotspur and the chairman of Tottenham Hotspur felt confident enough to say that in the Sunday Times several months ago that all 14 members of my board were put under surveillance."
She added: "The Metropolitan Police are now conducting an investigation into that surveillance.
"There has been all kinds of behaviour here that I could not have anticipated which, believe me, has not been pleasant in the last 12 months."
A deal with West Ham and Newham Council to use the stadium in Stratford, east London, after the 2012 Games collapsed last month amid legal challenges, with the Government announcing that the stadium would remain in public ownership. Tottenham had already lost out to West Ham in the race to become the OPLC's first choice to move into the stadium after the Games.
Legal challenges by Tottenham Hotspur and Leyton Orient, plus an anonymous complaint to the European Commission, had led to fears that court action could drag on for years while the stadium remained empty.
A new tender process is being launched by the OPLC and the showpiece venue, complete with an athletics track, will now remain in public ownership and be rented out to an anchor tenant.
Tottenham rejected Baroness Ford's comments and issued a statement through their lawyers, which read: "The club did not undertake, instruct or engage any party to conduct surveillance on any member of the OPLC Committee and we consider the making of this baseless accusation to be wholly inappropriate and irresponsible.
"We totally reject the accusation in the strongest possible terms."