The TARDIS lands on a remote island, surrounded by a sea of acid. They meet Arbitan, keeper of the Conscience of Marinus who forces the travellers to go in search of five keys.

Liz has been captured by Reegan who is holding the three aliens captive. The Doctor suspects Quinlan's part in the conspiracy, but Quinlan is killed before he can reveal the truth.

With Peter Davison and Ben Foster - chatting about Doctor Who music.

Welsh actor who appeared in Torchwood

Actor who appeared in the 2006 story Rise of the Cybermen

Sheila  Dunn was an actress who worked primarily on television.

In 1965 she married Doctor Who director Douglas Camfield, after which she appeared in numerous drama series and serials directed by him, including Shoestring, Target, and three of his Doctor Who serials.

She appeared in two editions of The Wednesday Play in the early part of her career. 

She also appeared in episodes of Z-Cars, The Bill and Kessler.

Her most prolific role in the latter stages of her career was in the Harry Hill TV series in which she played Harry's mother.

Ron Pember  is a British actor, stage director and dramatist, best known for his role as Alain Muny in the 1970s BBC drama series Secret Army.

He appeared in the Doctor Who Radio play Slipback.

Pember played the part of the psychopathic taxman in the Red Dwarf episode "Better Than Life". He also played the part of Dennis Timson in series 4 to 7 of Rumpole of the Bailey.

He retired from acting in 1992 after a stroke.

Derek Martin was born in Bow East London, he enjoyed his education and left school with good grades. At the age of 15 his first job was as an apprentice to an Estate Agents and Surveyors, after this he worked in the construction industry, soft drinks advertising. Having found little fullfillment in any of these careers he joined the RAF at 18, becomming a 'snow drop' or RAF military police. He eventually left the RAF with the rank of corporal, he then worked in a wood veneer facility and a brewery - which being a teetotaller he found somewhat unfullfilling. He started working at Smithfield Meat Market and left for a very short lived career as a proffesional gambler, he returned to work at Smithfield and married for the first time. Derek then started a career in motor-racing, his ambition was to be world champion. He gave up on this career due to personal pressures and eventually divorced his first wife. It was also during this period he fell foul of the law and found himself in Court No 1 of the Old Baily. He was on charges of Recieving and Larceny, but was found to be not guilty by a Jury of his peers. After this he decided to turn his hand to acting (after the strength of his recent performance).

He went to a small coffee house in Old Compton Street Soho, which was frequented by a number of actors, he asked some of the actors who their agent was and after receiving a telephone number Derek rang them. He asked for an appointment and informed the agency that he had performed repertory theatre in a number of obscure towns, close to where he had been stationed in the RAF. His first job was as a walk on in a TV production. He caught the bug, left Smithfield and decided on the life of an actor. After a large number of small TV parts he then decided to become a Stuntman and worked on many different techniques, including horses, car crashing, fencing, fights and arranging action scenes.

During his career as a Stuntmen he avoided serious injuries and with the exception of a broken collar bone doing a horse fall in Elizabeth R. Three weeks after this accident he was back in the studio shooting another scene with his arm still in a Sling. He remarried and eventually had twin sons, David and Jonathan. By now Derek had recieved many offers of acting work he then decided to stop doing stuntwork and move into acting full time. He moved into acting and recieved his first big break in 1977 playing a leading character in the controversial drama series Law and Order, this put his name and face on the map.

Ronald Fraser was an English character actor, who appeared in numerous British plays, films and television shows from the 1950s to the 1990s. He was perhaps best known as Basil "Badger" Allenby-Johnson in the 1970s television series The Misfit.

He played Joseph C in the 1986 story The Happiness Patrol.

Ronald Fraser was born in Ashton-under-Lyne, Lancashire, the son of an interior decorator and builder from Scotland. He attended Ashton Grammar School. He was educated in Scotland and did national service as a lieutenant in the Seaforth Highlanders. While serving in Benghazi in North Africa, he appeared in the comic play French Without Tears by Terence Rattigan. He trained as an actor at RADA until 1953 and soon appeared at the Glasgow Citizens' Theatre. He joined the Old Vic repertory company in 1954, making his first London appearance in The Good Sailor, a stage adaptation of Herman Melville's novel, Billy Budd.

In the West End, he appeared in The Long and the Short and the Tall, The Ginger Man, The Singular Man, Androcles and the Lion, The Showing Up of Blanco Posnet, Purple Dust by Seán O'Casey, Entertaining Mr Sloane, Joseph Papp's production of The Pirates of Penzance and High Society. He also played Falstaff in a production of The Merry Wives of Windsor at the Open Air Theatre, Regent's Park. His only Broadway show was the flop La Grosse Valise byRobert Dhéry, Gérard Calvi and Harold Rome.

He appeared in nearly 50 films and numerous television roles, mostly comedies

Actor who appeared in the 1971 story Terror of the Autons.

Other appearances include parts in Dixon of Dock Green, Holby City and Heartbeat.

John Bennett was an English actor.

He had two major roles in Doctor Who. he played General Finch in the 1974 story Invasion of the Dinosaurs and Li H'sen Chang in the 1977 story The Talons of Weng-Chiang

Born in Beckenham, Kent, he was educated at Bradfield College in Berkshire, then trained at the Central School of Speech and Drama, followed by a wide Rep experience including Bromley, Bristol Old Vic, Dundee, Edinburgh Festival and Watford before going to London's West End.

Often cast as a villain, he had many roles on television including Porridge, Survivors, The Avengers, Bergerac, The Professionals and four episodes of The Saint.  He is also well remembered as Philip Bosinney in the BBC's 1967 adaptation of The Forsyte Saga, but also appeared in over three hundred TV productions including God's Architect;Blake's 7; I, Claudius; Rome; Rosemary & Thyme; Saracen; Honey Lane; Special Branch; Softly, Softly; Mulberry; Tales of the Unexpected and Anna Karenina. One of his last televised roles was in an episode of Jonathan Creek.

His film roles included The Fifth Element (1997), Charlotte Gray (2001) and Minority Report (2002). He also played an undercover detective in Victim (1961) (starring Dirk Bogarde), but the role was uncredited.

His theatre roles included Yasha in The Cherry Orchard and Henry Percy (Hotspur) inRichard II both for John Gielgud, Exton in Richard II and Volscian Senator in Coriolanus(Almeida Theatre), Marley's Ghost in A Christmas Carol (Royal Shakespeare Company) and Uncle in Inner Voices (Royal National Theatre), as well as working extensively at theRoyal Exchange Theatre, Manchester. He starred in many West End musicals includingOn Your Toes (Palace), Marilyn (Adelphi), The Sound of Music (Apollo Victoria), The King and I (London Palladium), The Baker's Wife (Phoenix) and was nominated for an Olivier Award for Best Supporting Performance in a Musical for his performance as Louis Epstein in Jolson The Musical (Victoria Palace and Royal Alexandra Theatre, Toronto). His last stage role was as Conrad in Gates of Gold by Frank McGuinness with William Gaunt at the Finborough Theatre, London, in December 2004.

In radio, he had been a member of the BBC Drama Repertory Company, and his broadcast parts included roles in programmes that ranged from Shakespeare to Paul Temple.