Deputy Met Commissioner Tim Godwin has been announced as the new Acting Commissioner for the service by Home Secretary Theresa May.
Godwin, who in addition to his current role at Scotland Yard is also the lead on mobile phone crime for the Association of Chief Police Officers, will temporarily take over from Commissioner Sir Paul Stephenson, who resigned on Sunday. May said he will take over "as soon as possible".
Bernard Hogan-Howe will be acting commissioner in Godwin's stead.
Godwin was previously Acting Commissioner when Stephenson took time off in December 2010 for medical reasons.
May also used her parliamentary statement to announce a full parliamentary review into police corruption. Elizabeth Filkin, who is a former parliamentary standards commissioner will review "the ethical considerations that should, in future, underpin the relationships between the Metropolitan Police and the media, how to ensure maximum transparency and public confidence, and provide advice."
There will also be a review into the general relationship between the police and the press by Her Majesty's Inspectorate of Constabulary, to "consider instances of undue influence, inappropriate contractual arrangements and other abuses", and a review into the Independent Police Complaints Commission.
These inquiries are in addition to the judge-led inquiries into phone hacking and the media announced in parliament last week.
Shadow Home Secretary Yvette Cooper made a strong rebuttal to May's statement, questioning the government's commitment to the policy of elected police commissioners.