Hundreds of firms and individuals linked to rogue private investigators could be named after the chairman of the police unit blocking their release resigned, an MP has suggested.

Sir Ian Andrews resigned as chairman of the Serious Organised Crime Agency (Soca) after it emerged he had failed to declare his directorship with legal and management consultancy Abis Partnership - contrary to the agency's strict rules.

His decision to step down comes amid a furore surrounding a list of 102 firms and individuals linked to rogue private investigators that Soca recently handed over to the Home Affairs Select Committee on condition that their names are not revealed.

But Keith Vaz MP, chairman of the Commons Committee, which is in possession of the coveted list, said he would ask Sir Ian's successor to review this decision.

Mr Vaz said: "Sir Ian was part of the decision-making process that required that the Home Affairs Select Committee kept the lists that Soca sent us confidential. I shall be writing to his successor to ask if he or she will now review this decision."

Pressure had been mounting on Sir Ian and Soca to release the so-called "blue-chip hacking" list linked to Operation Millipede, which led to the conviction of four private detectives for fraud last year.

The list features eight firms that featured in evidence in the prosecutions, as well as 94 other organisations which were relevant to the inquiry but not used in evidence. A total of 22 law firms feature on the 102-strong list, alongside several insurance companies, financial services groups and two celebrities, among others.

A Soca spokeswoman: "The Home Secretary has today accepted the resignation of Sir Ian Andrews as chair of the Soca board. Sir Ian offered his resignation after realising he had neglected to register his directorship of Abis Partnership Ltd. The Soca code demands that all directors' interests are declared."

Sir Ian, who will officially step down on Friday, wrote to the Home Affairs Select Committee after it emerged last week that his wife, Moira Andrews, is employed as the head lawyer for Good Governance Group (G3) - a global private investigations firm.

Both the Home Office and Soca have denied that Sir Ian's departure is connected to the revelations concerning his wife.