Question: Which English actor, raconteur, and diarist was featured on the regular cast of Carry On Screaming?

Context paragraphs:
Fenella Fielding: Fenella Fielding (born 17 November 1927) is an English stage, film and television actress, popular in the 1950s and 1960s and known as "England's first lady of the double entendre".  She is known for her seductive image and distinctively husky voice.  Fielding appeared in two "Carry On" films, "Carry on Regardless" (1961) and "Carry on Screaming! " in 1966.

Mary-Claire Carter: Mary-Claire Carter is a fictional character from the BBC medical drama "Holby City", played by actress Niamh McGrady.  She first appeared in the eleventh series episode "Spin", broadcast on 22 September 2009.  The character was introduced by Tony McHale.  Between her arrival and January 2013, Mary Claire appeared on a recurring basis, sometimes with months between appearances, as an agency nurse on Keller and AAU wards.  McGrady was promoted to a regular cast member in early 2013 by newly appointed executive producer, Oliver Kent - alongside the introductions of three characters.  Her first appearance, as a regular cast member, aired on 23 April when Mary-Claire received a staff nurse job on the AAU ward.  She is characterised as a blunt and easily distracted character, yet a brilliant nurse.  Her strong point is not diplomacy, but scratch between the surface and you'll find a heart of gold.  McGrady has described her as "cheeky, flirtatious, and trouble."

Mission: Impossible (1988 TV series): Mission: Impossible is an American television series that chronicles the missions of a team of secret American government agents known as the Impossible Missions Force (IMF).  The show is a revival of the 1966 TV series .  The only actor to return for the series as a regular cast member was Peter Graves who played Jim Phelps, although two other cast members from the original series (Greg Morris and Lynda Day George) returned as guest stars.  The only other regular cast member (unseen) to return for every episode was the voice of "The Tape" (in this series, "The Disc"), Bob Johnson.

Carry On Screaming!: Carry On Screaming is a British Comedy and the twelfth film in the series of "Carry On" films to be made and was released in 1966.  It was the last of the series to be made by Anglo-Amalgamated before the series moved to The Rank Organisation.  Of the regular cast, it features Kenneth Williams, Jim Dale, Charles Hawtrey, Joan Sims, Bernard Bresslaw and Peter Butterworth.  It also features Harry H. Corbett in his only Carry on and Fenella Fielding making her second and final appearance.  Angela Douglas makes the second of her four Carry on appearances.  "Carry On Screaming" is a parody of the Hammer horror films, which were also popular at the time.

Stargate Atlantis (season 4): The fourth season of "Stargate Atlantis", an American-Canadian television series, began airing on September 28, 2007 on the US-American Sci Fi Channel.  The fourth season concluded after 20 episodes on March 7, 2008 on Sci Fi.  The series was developed by Brad Wright and Robert C. Cooper, who also served as executive producers.  Amanda Tapping (Col. Samantha Carter) joins the cast as a regular for 14 episodes, Jewel Staite (Dr. Jennifer Keller) was a recurring character for eleven episodes, while regular cast member Torri Higginson (Dr. Elizabeth Weir) was a recurring cast member for four episodes.  Other season four regular cast members include Joe Flanigan, David Hewlett, Rachel Luttrell and Jason Momoa.

Merlin (series 3): The third series of "Merlin" began on 11 September 2010.  Series three regular cast members include Colin Morgan, Bradley James, Katie McGrath, Angel Coulby, Anthony Head, and Richard Wilson, as well as Emilia Fox joining the regular cast.  John Hurt took his previous role as the voice of the Great Dragon but was no longer one of the regular cast (though he continued to provide the opening narration for the series).  Series three consists of 13 episodes.  The series three premiere was watched by 6.49 million viewers.

Kenneth Williams: Kenneth Charles Williams (22 February 1926 – 15 April 1988) was an English actor, best known for his comedy roles and in later life as a raconteur and diarist.  He was one of the main ensemble in 26 of the 31 "Carry On" films, and appeared in many British television programmes and radio comedies, including series with Tony Hancock and Kenneth Horne.

Tom Clegg (actor): Tom Clegg (1915 – 1996) was an English actor, who had a number of small roles in film and television during the 1950s, 1960s and 1970s.  He is known for appearing in a number of "Carry On films", especially "Carry On Screaming! ", where he played the role of Oddbod.

Smallville (season 7): Season seven of "Smallville", an American television series, began airing on September 27, 2007.  The series recounts the early adventures of Kryptonian Clark Kent as he adjusts to life in the fictional town of Smallville, Kansas, during the years before he becomes Superman.  The seventh season comprises 20 episodes and concluded its initial airing on May 15, 2008, marking the second season to air on The CW television network.  Regular cast members during season seven include Tom Welling, Michael Rosenbaum, Kristin Kreuk, Allison Mack, John Glover, Erica Durance, Aaron Ashmore, and Laura Vandervoort.  In addition to bringing in new regular cast members this season, the "Smallville" team brought in familiar faces from the Superman media history, old villains from the show's past, as well as new DC Comics characters.

Hugh Futcher: Hugh Futcher (born 29 October 1937 in Portsmouth, Hampshire) is an English actor in theatre, television and film.  He was a member of the stock company of the Carry On films, with notable parts in "Carry On Spying", "Carry On at Your Convenience", and "Carry On Behind".  Other films include Roman Polanski's "Repulsion" (as Colin's pubmate Reggie) and the Herman's Hermits musical "Mrs. Brown, You've Got a Lovely Daughter".

Supporting paragraphs: Carry On Screaming! Kenneth Williams
Answer: Kenneth Williams