Nine names have been removed from a controversial list of clients of rogue private detectives just days before it is expected to be published, Scotland Yard has said.
It comes after Trevor Pearce, director general of the Serious Organised Crime Agency (Soca), refused to release the document despite an ultimatum from MPs earlier this week.
His rejection paves the way for the Home Affairs Select Committee to publish the names on the list - featuring law firms, insurance companies, financial services groups and celebrities - on Monday, following threats from chairman Keith Vaz.
However a Scotland Yard spokesman confirmed that nine names have been withdrawn from the file as they are subject to live investigations.
"In all, nine names have been removed from the Soca Operation Millipede list at the request of the Metropolitan Police Service as they are subject to live and an ongoing investigations," he said.
He added that five of the names relate to Operation Tuleta, the force's probe into computer hacking and other alleged privacy breaches, while four relate to other ongoing investigations.
The names of around 100 firms and individuals who allegedly used corrupt private investigators was handed from Soca to the Committee earlier this year on condition it was not published - sparking a row over transparency.
In his letter to Mr Vaz, Mr Pearce said: "I remain firmly of the view that publishing the list of clients would affect ongoing investigations and inquiries."
Following a heated evidence session on Tuesday, Mr Vaz told Mr Pearce and Stephen Rimmer, Soca's interim chairman, the Committee would publish the list on Monday if Soca did not do so first.
The so-called ''blue-chip hacking'' list was drawn up earlier this year at the request of the Committee and relates to Soca's Operation Millipede, which led to the conviction of four private detectives for fraud last year.
In the letter, Mr Pearce said Soca provided the client list to the Committee in accordance with Cabinet Office guidelines on the handling of sensitive information in confidence to select committees.
Mr Vaz confirmed on July 15 that the Committee would treat the list as confidential, Mr Pearce said.
The director general added that the Information Commissioner, the data watchdog, and the Metropolitan Police do not want the names on the list to be published.
Mr Pearce said: "I note the points raised by the Committee in respect of individuals and companies wanting to know whether they are on the list, as this would inform their engagement with private investigators.
"All businesses should take proactive measures to ensure that where they use private investigators they do so in a lawful manner, irrespective of whether they are concerned as to whether or not they are on the list."
He added: "I am clear, as is the Soca chairman, that Soca's responsibility in ensuring the integrity of an investigative process in the interests of justice has not changed and that therefore the confidential material as presented to and agreed with you should remain confidential."
Up to 100 individuals may have had their details accessed by the private investigators, Mr Pearce previously revealed.
The Information Commissioner's Office (ICO) last week announced its own investigation into nearly 100 of the private eyes' clients.
Commenting on the row, Prime Minister David Cameron said: "There is the specific issue of an agreement between Soca and the Home Affairs Select Committee, and I think that is a matter for them.
"Select committees are quite correctly independent of Government. If they reach an agreement with an independent agency about confidentiality that is a matter for them, that is not a matter for me.
"More generally, let me make two points. Hacking is wrong. It is against the law, and people who do it should be punished. As I've said on many occasions, the law should follow where the evidence leads.
"Secondly, we do have in our country - and I think it's right - an open system of justice. That's the way it should be. And that applies, as far as I'm concerned unless there are specific exemptions as there are in some very specific cases, the open system of justice should be just that."