Metropolitan Police Commissioner Sir Paul Stephenson has resigned following the phone hacking scandal.
Britain's most senior police officer said he had no knowledge of the extent of the practice and his integrity was "completely intact".
Sir Paul has faced criticism for hiring former News of the World executive Neil Wallis - who was questioned by police investigating hacking - as an adviser.
He said his links to the journalist could hamper current investigations.
Sir Paul said in a statement: "I have taken this decision as a consequence of the ongoing speculation and accusations relating to the Met's links with News International at a senior level and in particular in relation to Mr Neil Wallis."
He added: "Let me state clearly, I and the people who know me know that my integrity is completely intact.
"I may wish we had done some things differently, but I will not lose sleep over my personal integrity."http://www.bbc.co.uk/news/uk-14180043
They're running like lemmings just now