WEST Ham believe Spurs hired a private investigator to steal bank and telephone records of senior executives during the Olympic Stadium bid process.

A statement by the club said that it had contacted police about the allegations – which they believe could result in prison sentences if proved – and was treating them with the “utmost seriousness”.

The argument relates to the bitter process to select which of the two clubs would move into the Olympic Stadium after the Games next year – which West Ham won in March.

The club believes Tottenham hired an investigator to work out West Ham's strategy for the bid process.

In the statement, West Ham said: “This matter is being treated with the utmost seriousness by the club, especially given the methods claimed to have been used to obtain this personal information in relation to reported breaches of the Data Protection Act as a result of the unlawful acquisition of bank and telephone records belonging to senior executives at the club and the Olympic Park Legacy Committee.

“This activity, if proven, constitutes serious criminal conduct and can attract custodial sentences for perpetrators of the crime.

“In addition to the police, the matter is also now in the hands of the Information Commissioner's Office, which investigates allegations of data protection offences.”

Tottenham attempted to seek a judicial review into the decision to hand the stadium to West Ham, but failed at a hearing at the High Court in June.

Spurs said they would not be commenting on West Ham's allegations when contacted by the Haringey Independent.