The Metropolitan police has announced that more public figures may have been the victims of phone hacking than previously thought.

After reviewing existing and new evidence, Scotland Yard admitted it may have misinformed potential hacking victims by telling them they had not been targeted by the News of the World.

Scotland Yard said in a statement it had begun reviewing new evidence handed over by the paper's owner News International. It is also looking again at the contents of notebooks seized in 2005 from Glenn Mulcaire, the private investigator employed by the title.

"As a result, the team have... identified some individuals who were previously advised that there was little or no information held by the MPS [Metropolitan Police Service] relating to them within the case papers", the force said.

It added it was unclear at this stage if mobile phones belonging to those individuals had been hacked by Mulcaire, but it would be notifying them all as a matter of urgency as it begins what it described as an "important and immediate new line of enquiry".

The evidence handed over by News International includes emails sent by Ian Edmondson, the news editor it sacked last month, and retrieved from his work computer during an internal inquiry.

The Met also said it would contact everyone who it believed may have had their phones hacked. That marks a dramatic change of policy for the Met. Previously, only a handful of people had been informed they were targeted by Mulcaire, who was jailed for illegally intercepting voicemail messages on phones belonging to members of the royal family.

Scotland Yard is now taking a more proactive approach by undertaking to contact all those who it believes may have been hacked, which could include hundreds of well know people.

Deputy Assistant Commissioner Sue Akers, who is leading the new police investigation, said: "We will be as open as we can be and will show them all the information we hold about them, while giving them the opportunity to tell us anything that may be of concern to them".

She added: "In time, we will go beyond this group of individuals and make contact with everyone who had some of their personal contact details found in the documents seized in 2005. This will ensure all of those who have been affected in some way are made aware of the information we have found relating to them."

A freedom of information request submitted by the Guardian revealed Mulcaire's notebooks contain the mobile phone numbers belonging to thousands of individuals.

I do wish they'd stop calling this "phone hacking".

It's actually, voicemail service access code guessing, and since a lot of people don't actually change their code from the default, it isn't all that clever or technically challenging.

It was down to the fact that the default passwords had not been changed from 0000.

I did not know that. Such negligence is practically criminal. In my company, failing to change your password from the default and exposing confidential material as a consequence would be considered gross misconduct.