Home Affairs Select Committee chairman Keith Vaz has written to the Met Police's Assistant Commissioner Cressida Dick to ask if the force has any further interest in the companies on a list of names linked to rogue private investigators.
He has asked Ms Dick, as well as the Information Commissioner's Office, to confirm when the public will be able to see those names, whose identities are currently being protect at the behest of the Serious Organised Crime Agency (Soca.)
The list, which was created by Soca, was passed to the Home Affairs Select Committee on strict confidentiality grounds - prompting Mr Vaz to demand an explanation as to why it should be kept secret.
It breaks down firms that featured in evidence in prosecutions of Operation Millipede, the Soca investigation that led to the conviction of private detectives for fraud, as well as firms that were relevant to the inquiry but not used in evidence.
Chairman Keith Vaz said the Home Affairs Select Committee "remains concerned" after it was handed a list of 102 names of companies and individuals linked to rogue private investigators.
The Committee remains concerned that it holds a list that Soca [Serious Organised Crime Agency] has classified as secret, even though it is evidence given as part of our inquiry.
This is an important step forward in establishing the facts.
Mr Vaz also confirmed there are five organisations or individuals on the list who are being investigated as part of Operation Tuleta, Scotland Yard's investigation into allegations of computer hacking.
Immigration Minister Mark Harper has backed the Government's new UK Visas and Immigration Service to clear Britain's backlog of immigration cases.
The UK Border Agency was a troubled organisation for many years, which is why the Home Secretary took the decision to split the agency in March this year.
The new UK Visas and Immigration Service has a clear focus to improve visa performance and customer service, while the Immigration Enforcement Command concentrates on those who break our immigration laws.
Both now report directly to ministers, delivering greater transparency and accountability.
It will take a long time to clear the backlogs we inherited - but through the changes we have made we are in a much stronger position to do so.
Home Affairs Select Committee chairman Keith Vaz MP has criticised Home Secretary Theresa May following the Committee's latest report into the backlog of immigration cases in Britain.
The backlog of cases has now hit a staggering half a million people. This could fill Wembley Stadium to capacity six times over.
At the current rate it will take 37 years to clear and the Home Office cannot confirm that this is the last of the backlogs.
Theresa May described the UK Border Agency as 'closed, secretive and defensive', however, despite abolition nothing appears to have changed apart from the name. If people at the top are not replaced this will only be an exercise in rebranding as has happened in previous reincarnations.
There should be no more bonuses paid to any senior management at the Home Office until the backlogs are cleared.
After a raft of damning reports, Home Secretary Theresa May abolished the UKBA and replaced it with UK Visas and Immigration and an Immigration Enforcement command, which were brought back under the control of ministers.
The backlog of immigration cases at Britain's troubled border service has hit a "staggering" half a million people and at the current rate of progress will take nearly four decades to clear, a group of MPs has warned.
A rise in the number of foreign-national offenders living in the community as they await deportation was also discovered by the Home Affairs Select Committee in its latest report into the work of the now-defunct UK Border Agency (UKBA).
The committee warned that a recent move to scrap the agency and replace it with two new divisions - one in charge of immigration and visas, the other with border enforcement - was in danger of being an "exercise in rebranding".
It discovered that in the final quarter of last year, spending on external consultants at the agency rocketed from £27,000 in the previous three months to more than £500,000.
Keith Vaz, the chair of the Home Affairs Select Committee, has said that some police are able to "get away with corruption and incompetence" because of "broken systems of accountability". He said:
Broken systems of accountability and a patchwork of police standards and training, have allowed a minority of officers to get away with corruption and incompetence which is blighting an otherwise excellent service with dedicated officers.
The days of Dixon of Dock Green are over. The new landscape of policing requires a new type of police officer ready to meet the new challenges.
Honesty, integrity and transparency are essential components of the policing DNA.