Mark Bailey (known professionally as Bill Bailey) is an English stand-up comedian, musician and actor, known for appearing on Have I Got News for You, Never Mind the Buzzcocks, QI, and Black Books as well as his stand up comedy. He is a self proclaimed "confused hippie" known for his thin goatee and long hair.

Bailey was listed by The Observer as one of the 50 funniest acts in British comedy in 2003, and in 2007 he was voted number seven on Channel 4's hundred greatest stand-ups.

Bailey began touring the country with other comedians such as Mark Lamarr. In 1986 he formed a double act, the Rubber Bishops, with Toby Longworth (a former fellow pupil at King Edward's Bath) who was replaced in 1988 by Martin Stubbs. They achieved a certain amount of success on the club circuit, partly due to their rigorous schedule — sometimes as many as three or four gigs a night.

It was here that Bailey began developing his own unique style, mixing in musical parodies with deconstructions of or variations on traditional jokes ("How many amoebas does it take to change a lightbulb? One, no two! No four! No eight...") - according to comedy folklore, after a reviewer once criticised his act for its lack of jokes, Bailey returned the following night, at Queen Margaret College, Edinburgh, to perform a set composed entirely of punchlines.

Stubbs later quit to pursue a more serious career, and in 1994 Bailey performed Rock at the Edinburgh Fringe with Sean Lock, a show about an ageing rockstar and his roadie, script-edited by comedy writer Jim Miller. It was later serialised for the Mark Radcliffe show on BBC Radio 1. However, the show's attendances were not impressive and on one occasion the only person in the audience was comedian Dominic Holland. Bailey confessed in an interview with The Independent that he almost gave it up to do a telesales job.

He persevered, however, and went solo the next year with the one man show Bill Bailey's Cosmic Jam. The show was very well received and led to a recording at the Bloomsbury Theatre in London which was broadcast in 1996 on Channel 4 as a one-hour special called Bill Bailey Live. It was not until 2005 that this was released in DVD uncut and under its original title. It marked the first time that Bailey had been able to tie together his music and post-modern gags with the whimsical rambling style he is now known for.

After supporting Donna McPhail in 1995 and winning a Time Out award, he returned to Edinburgh in 1996 with a critically acclaimed show that was nominated for the Perrier Comedy Award. Amongst the other nominees was future Black Books co-star Dylan Moran, who narrowly beat him in the closest vote in the award's history.