Gray's Inn Tax Chambers has recruited the former solicitor to the board of the Inland Revenue as a door tenant.
Brian Cleave QC worked for the Inland Revenue for 32 years and was a solicitor to the board for nine years until his retirement in November 1999.
Cleave's move to the bar is unusual, because despite being made a QC (honoris causa) in 1999, he still has to complete a four-month pupillage.
Head of chambers Milton Grundy says: “We are pleased to maintain our links with the Solicitor's Office.
“We all enjoy the company of someone who was at times an old opponent for some of us.
“We discuss cases and the problems we have and the options that are available to us and Cleave will help us to see how the matter is going to look from a Revenue point of view.”
The set is one of two leading tax chambers at the London bar and houses several of the countries top earners, including tax silk David Goldberg QC who is said to earn over £2m a year.
Cleave was unavailable for comment.