The new chairman of the Committee on Standards in Public Life has been named as Sir Christopher Kelly.
The appointment of the former top Whitehall civil servant and current chairman of the Financial Ombudsman Service was announced by Prime Minister Gordon Brown.
Sir Christopher, 61, will take up his new post on January 1 for a non-renewable five-year term, Downing Street said.
The position, created by former prime minister John Major, involves holding politicians and public office-holders to account on matters of propriety.
The announcement follows criticism about the length of time it has taken to replace Sir Alistair Graham, the last chairman of the ethical watchdog, who left the post earlier this year.
A career civil servant, Sir Christopher was permanent secretary at the Department of Health from 1997 to 2000.
Mr Brown said: "Chris Kelly will bring to the role his significant experience in the public, private and voluntary sectors across a wide range of areas."
Sir Christopher is also chairman of the National Society for the Prevention of Cruelty to Children and a board member of the National Consumer Council, a post which he will be leaving shortly.
Sir Alistair left the job in April after former premier Tony Blair did not renew his contract. Critics claimed he had effectively been sacked for being too critical of the Labour Government.
Sir Christopher will be the first person to hold the position for a fixed period which cannot be renewed.
