Lord Phillips of Worth Matravers has been appointed the top judge in England and Wales, Downing Street has said.
Lord Phillips is well-known for cycling to court
He will replace the current Lord Chief Justice, Lord Woolf, who is due to step down in September.
Nicholas Addison Phillips, 67, was chairman of the inquiry into BSE. He is said to be popular among lawyers and pioneered using computers in court.
Lord Phillips was called to the bar in 1962, took silk in 1978 and became a Recorder in 1982.
He became a High Court judge in 1987 and an appeal court judge in 1995, later becoming a Lord of Appeal in 1999 and Master of the Rolls - in charge of the civil division of the court of appeal - in 2000.
As an appeal court judge, he presided over long and complex trials including that of the Maxwell brothers and the case of investment company Barlow Clowes.
He was made a Law Lord in January 1999 and is also well-known for cycling to and from court. He will be replaced as Master of the Rolls by Lord Justice Clarke.
A new post of President of the Queen's Bench Division of the High Court - will be taken by Lord Justice Judge.
Previously the Lord Chief Justice also presided over the Queen's Bench Division.