Rail regulator John Swift QC is leaving his controversial post to return to his former set as head of chambers.
Swift, who was head-hunted for the five year tenure as rail regulator, will take up his new post at Monckton Chambers in January.
Monckton Chambers is a premier European Union and competition law set with a strong aviation practice.
The current head, Richard Fowler QC, has completed his term in the post, but will continue to practise in his specialism as a European Union and competition law silk.
Swift specialises in the same field, bringing the number of leading silks in European Union and competition law at Monckton to six, and the total number of members to 26.
Swift said he had expansion plans for Monckton, although he would not say how exactly this was going to be achieved.
In his role as rail regulator he was the passengers' champion launching numerous scathing attacks against companies who failed to live up to their promises.
Notably, he has attacked Railtrack for excessive fares, misinformation over ticket suitability and the poor service provided by the telephone enquiry bureau.
He said he was satisfied that as rail regulator he had achieved his objective of giving the industry a structure to carry it into the 21st century.