Neither the humans or the Draconians are willing to believe the Doctor and Jo's story that someone is deliberately attempting to provoke a war between Earth and Draconia.

Sarah Smart was born on 3 March 1977 in Birmingham, West Midlands, England). She is an English actress.

Her career started as a child, notably in the television series Woof!. She is best known for a series of well-regarded television roles including Virginia Braithwaite, daughter of a lottery winning family in the comedy drama At Home with the Braithwaites. Sparkhouse (Red Production Company / BBC 2002); and her appearance in Jane Hall (Red Production Company /ITV1 2006) marked a fruitful link between Smart and television writer Sally Wainwright. Between 2008 and 2010, she featured as Anne-Britt Hoglund in Wallander, six feature-length adaptations of Henning Mankell's Wallander novels, for the BBC. 

Brian Cox, OBE is a British particle physicist, a Royal SocietyUniversity Research Fellow, PPARC Advanced Fellow and Professor at the University of Manchester. He is a member of the High Energy Physics group at the University of Manchester, and works on theATLAS experiment at the Large Hadron Collider (LHC) at CERN, near Geneva, Switzerland. He is working on the R&D project of the FP420 experiment in an international collaboration to upgrade the ATLAS and the CMS experiment by installing additional, smaller detectors at a distance of 420 metres from the interaction points of the main experiments. 

He is best known to the public as the presenter of a number of science programmes for the BBC, boosting the popularity of subjects such as astronomy; so is a science popularizer, and science communicator. He also had some fame in the 1990s as the keyboard player for the pop band D:Ream.

Michael Ladkin  played the RAF Pilot in the Doctor Who story The Faceless Ones.

He later became an agent

Shirley Cooklin played Kaftan in the Doctor Who serial The Tomb of the Cybermen.

She was married to the Doctor Who producer Peter Bryant and the role of Kaftan was written specially for her.

Also worked on Macbeth, Public Eye, Macbeth, Menace, Trog. Paul Temple, The Adding Machine, The Tyrant King, Detective, Z Cars, This Man Craig, Leave It to Todhunter, Onion Boys, The Adventures of Sir Lancelot, Dixon of Dock Green, The Children of the New Forest, Fabian of the Yard, Stage by Stage: The Relapse or, Virtue in Danger

Howell Evans was a Welsh actor, comedian, and singer who worked extensively in television and theatre roles in a career spanning over 60 years. 

He was best known for having played "Daddy" in the Sky1 TV comedy drama series Stella.

John Woodnutt was a British actor.

Born in London he made his acting debut at the Oxford Playhouse at the age of 18.

He had many television and film roles, including that of Henry VII in the first episode of The Six Wives of Henry VIII (1970); Sir Watkyn Bassett in the television version of Jeeves and Wooster (1990 to 1993); and Merlin and Mogdred in the children's adventure game programme Knightmare (1987-1990). One of his earliest television roles was in 1956 in the ITV drama One, broadcast live. He appeared five times in Z-Cars and once in Softly, Softly.

He appeared Doctor Who four times, in Spearhead From Space (1970) as Hibbert, Frontier In Space (1973) as the Draconian Emperor, Terror of the Zygons (1975) in the dual roles of Broton and the Duke of Forgill and The Keeper of Traken (1981) as Seron.

He appeared in The Avengers episode "Quick-Quick Slow Death" in 1966 and played "The Spidron" in the cult science fiction series The Tomorrow People in 1973. He also appeared in the Look and Read educational serial "The Boy From Space" in 1971, as the Thin Spaceman; in the 1976 HTV series Children of the Stones as the sinister butler Link.; and in the 1978 series The Doombolt Chase. 

In the 1980s, he played various guest roles in several television movies such as Hitler's S.S.: Portrait in Evil, starring Bill Nighy and John Shea. In the BBC Scotland television series of The Secret Garden, made in 1975, he played the part of Mr. Archibald Craven. He appeared in producer Barry Letts's classic serials Sense and Sensibility, Stalky & Co., and The Pickwick Papers. He played the Senior Tutor in Porterhouse Blue, appeared regularly as Sir Watkyn Bassett in the Jeeves and Wooster series alongside Stephen Fry and Hugh Laurie and also appeared briefly in the comedy sketch show Paul Merton: The Series in the early 1990s.

Radio and television Sherlock Holmes stories in which he appeared included the BBC Radio 4 adaptation of The Hound of the Baskervilles and, as Mr. Merryweather, The Adventures of Sherlock Holmes with Jeremy Brett in the episode entitled "The Red-Headed League". He also made an appearance in the 1965 Douglas Wilmer Sherlock Holmes series on the BBC.

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.

Robert Beatty was a Canadian actor who worked in film, television and radio for most of his career and was especially known in the UK.

Born in Hamilton, Ontario, Beatty began his acting career in Britain in 1939.

Beatty's film credits include: San Demetrio London (1943), Another Shore (1948), Captain Horatio Hornblower (1951), The Square Ring (1953), The Amorous Prawn (1962), 2001: A Space Odyssey (1968), Where Eagles Dare (1968), The Pink Panther Strikes Again (1976), Superman III (1983), Minder on the Orient Express (1985) and Superman IV: The Quest for Peace (1987).

He appeared in British television shows such as Dial 999 (a co-production between Britain's ABC and the US company Ziv), Doctor Who ("The Tenth Planet" as General Cutler), Blake's 7 ("The Way Back" as Bran Foster), The Gathering Storm, The New Avengers, and Minder. He was in Franco Zeffirelli's TV mini-series Jesus of Nazareth and the American series of Ray Bradbury's The Martian Chronicles. Portrayed Ronald Reagan in Breakthrough at Reykjavik (Granada Television UK 1987).

Beatty played Philip Odell, a fictional Irish detective created by Lester Powell, between 1947 and 1961. The series debuted on BBC radio with the story "Lady in a Fog" in October 1947. The series was made available to overseas broadcasters by the BBC Transcription Service. His other radio credits included Shadow of Sumuru on the BBC Home Programme in 1945-46, Shadow Man on Radio Luxembourg in 1955, Destination - Fire! on BBC (early 1960s), General Sternwood in a BBC version of Raymond Chandler's The Big Sleep (1977), Pay Any Price (BBC 1982), The Mystery of the Blue Train (BBC 1985/1986), and as Henry Hickslaughter in Elizabeth Troop's Sony Award winning adaptation of Graham Greene's short story Cheap In August (1993).

_{Biography from the Wikipedia article, licensed under CC-BY-SA}