Sir Norman Bettison has resigned as chief constable of West Yorkshire Police after allegations that he was involved in a cover-up of the Hillsborough disaster.
Sir Norman first came under pressure earlier last month after he was named in the Hillsborough Independent report.
West Yorkshire Police Authority referred Sir Norman to the Independent Police Complaints Commission (IPCC), which is investigating his role.
Sir Norman said he resigned because his presence was proving a "distraction to policing" at West Yorkshire Police, and "not because of any allegations about the past".
ITV News' Correspondent Stephen Douglas reports:
The IPCC has confirmed it is pursuing two separate investigations - the first is looking at "potential criminal offences" and the second "misconduct matters".
Whilst Sir Norman's resignation would not preclude a potential conviction, it does mean he can not be disciplined if the second investigation finds him at fault.
It is not yet clear whether Sir Norman will receive all of the £83,000 pension he is entitled from his time as Chief Constable of Merseyside Police.
Reacting to the news of resignation, the chairwoman of the Hillsborough Families Support Group, Margaret Aspinall, said she was "delighted" that he was leaving.
Sir Norman released the following statement announcing his resignation:
Yesterday, a Hillsborough survivor and former civil servant told ITV News that Sir Norman had told him about a 'cover-up' shortly after the 1989 stadium tragedy.
Sir Norman Bettison denies that he has done anything wrong and says he is sure the IPCC will clear him.
Last month, he told Lucy Manning that "there's nothing I'm ashamed of" over Hillsborough.