The public naming of law firms linked to rogue private investigators will be delayed by at least two weeks, MPs have confirmed. 

The Commons Home Affairs Select Committee said today it had agreed to hold off publishing a list of around 100 individuals and firms that were clients of four investigators jailed following Operation Millipede.

Committee chair Keith Vaz had threatened to publish the list, which includes 21 law firms, earlier this week after it was provided by the Serious Organised Crime Agency (SOCA).

However, that has been put on hold while the Information Commissioner Christopher Graham investigates the scale of potential wrongdoing. Graham has agreed to report his findings to the committee by 23 September.

Graham had appealed to the committee not to publish information related to Operation Millipede saying it could ‘make it more complicated’ for his investigation to succeed.

Vaz said: ‘The Information Commissioner has given the committee an explicit commitment that he will pursue this matter to its appropriate end and that the victims will receive justice. 

‘He firmly agrees with the committee that these organisations and individuals need to act within the law. We are pleased that these matters are now subject to a thorough investigation albeit one delayed for several years.

‘To ensure that this investigation brings those clients who have committed illegal acts to justice we have asked Mr Graham to come before the committee after his scoping exercise. This will allow us to reassess whether his investigation fulfils all that is required. We will then decide on the next steps.’

Vaz has also written to justice secretary Chris Grayling asking for extra resources to fund the ICO investigation.

He also asked for stronger penalties for offences under section 55 of the Data Protection Act amid ‘universal agreement’ they are currently too lenient.

‘The introduction of a custodial sentence would provide a more effective deterrent, particularly since offences of this kind are often committed for commercial gain, and a small fine is unlikely to prove effective.’

Last month SOCA handed over to the ICO the list of 98 ‘blue chip’ clients of criminal private investigators. The ICO then set in train an investigation with a view to prosecuting breaches of the Data Protection Act.

Graham said the investigation will be thorough and transparent, but warned that publishing names would hinder the chances of a successful prosecution. ‘It’s not clever to start a criminal investigation by publishing the names of everyone and everything you’re investigating,’ he said. ’That’s why we’ve stated we’re not publishing the list at this stage, and why I’ve written to Keith Vaz MP to urge similar patience on the part of his select committee.’