Police investigations into phone-hacking, privacy breaches and corrupt payments could cost £40m over four years, the officer in charge of the inquiries said today.

Deputy Assistant Commissioner Sue Akers told the Commons Home Affairs Select Committee that while "an enormous amount of money" is being spent on the probes, she is not concerned by the fact that only just over half the possible victims have been notified and 13 people charged.

So far, eight people including former News International chief executive Rebekah Brooks and David Cameron's ex-spin doctor Andy Coulson have been charged under Operation Weeting, which is looking at alleged phone-hacking.