Birmingham City chairman David Gold and club secretary Julia Shelton are to be interviewed by City of London Police as the two-year investigation into corruption in football comes to a conclusion.

The pair will be interviewed voluntarily as witnesses and not suspects, and are expected to be questioned in connection with the allegations of false accounting and conspiracy to defraud which led to the arrests of co-owner David Sullivan and chief executive Karren Brady in April.

Gold said he could not comment on the matter but the fact he is being interviewed after a dossier of ‘evidence’ was delivered to the Crown Prosecution Service last week indicates police are still not content they have enough to bring any charges.

Last week detectives from the City of London economic crime unit, the country’s top fraud squad, formally requested advice from the CPS on whether there was sufficient proof to charge any of the individuals following an exhaustive inquiry. Prosecutors will now ask counsel to decide whether police have sufficient evidence to charge any of those investigated.

Seven individuals are at the centre of the investigation. As well as Sullivan and Brady, Portsmouth manager Harry Redknapp, Peter Storrie, Portsmouth’s chief executive, Milan Mandaric, the Leicester chairman, Amdy Faye, the Charlton Athletic midfielder, and the agent Willie McKay are also named. All seven strongly deny any wrongdoing.

The police probe has involved some of the game’s big names but there has been criticism of the police’s handling of the investigation.

The house of Portsmouth manager Harry Redknapp was raided by police last November but Redknapp won damages in May after the High Court ruled the dawn raid on his home had been unlawful.

Sullivan claimed he felt ‘personally violated’ and ‘almost rather raped’ after he was arrested in April, while St Andrew’s has also been raided and documents removed earlier this year.