The Doctor and his friends witness Forrester murder Arnold Farrow. Ian and Barbara watch as one of the 'giants' empties the sink in which the Doctor and Susan are hiding.

The Doctor contributes a DVD commentary to a cult 1970s horror movie re-release. Fifth Doctor adventure stars Peter Davison and Sarah Sutton.

With the shapeshifting Zygons appearing everywhere across Britain, it is now impossible to know who to trust. Only the Doctor is still standing in their way, but will he be able to save his friends even as he attempts to stop a war?

Part 2. Shapeshifting Zygons are everywhere in the UK, and there is no way of knowing who to trust. With UNIT neutralized, only the Doctor stands in their way. But how do you stop a war? And what can the Doctor do to save his friends?

Barney Harwood  is an English television presenter and actor, known for his work with CBBC. 

He co-hosted the Doctor Who tie-in programme Totally Doctor Who. He played  the Control Voice in an episode of the Doctor Who spin off animated series The Infinite Quest. He also appeared in the Doctor Who episode "Love & Monsters", which was first transmitted on 17 June 2006.

For CBBC, he presented Prank Patrol and was a voice-over commentator for The Smokehouse, while on BBC Two, he co-presented Basil's Swap Shop (a re-make of Multi-Coloured Swap Shop), alongside Basil Brush.

Previous work for CBBC included gameshow Crush in 2004, Sport Relief Gets Sub'd!, a Sport Relief 2006 show and as co-presenter of Smile, which aired each Sunday on BBC Two until 26 August 2007 and saw him win a Children'sBAFTA for best presenter. 

In July 2007, Harwood fronted The Sorcerer's Apprentice, a daily reality series following a group of children learning magic at a Harry Potter-style boarding school.[3] Bear Behaving Badly, a 26-part sitcom starring Harwood and Nev the bear from Smile, was broadcast on BBC One between September and October 2007.[4] In February 2008, Harwood starred as the 'hidden' celebrity in an episode of Hider in the House.

Harwood's worked on the series Inside Life which is the children's companion series to the BBC Natural History Unit's Life. Harwood narrates all ten programmes.

On 13 December 2010 it was revealed on the BBC's Blue Peter that Harwood would be the new presenter on the show, taking over from Joel Defries.

Lindsay Duncan is a Scottish stage, television and film actress. 

On stage she won two Olivier Awards and a Tony Award for her performance in Les Liaisons dangereuses (1985–1986) and Private Lives (2001–2002), and she starred in several plays by Harold Pinter. 

Her most famous roles on television include: Barbara Douglas in Alan Bleasdale's G.B.H. (1991), Servilia of the Junii in the HBO/BBC/RAI series Rome (2005–2007), and Adelaide Brooke in the Doctor Who special ‘The Waters of Mars’ (2009). On film she voiced the android TC-14 in Star Wars Episode I: The Phantom Menace (1999), and she played Alice's mother in Tim Burton's Alice in Wonderland (2010). She was awarded a CBE in 2009 for services to drama.

Duncan was born in Edinburgh, Scotland. She attended King Edwards VI High School for Girls in Birmingham through a scholarship.

Duncan joined London's Central School of Speech and Drama at the age of 21. She first appeared in two small roles in Molière's Dom Juan at the Hampstead Theatre in 1976. She then spent several years doing rep in East Anglia before joining the Royal Exchange Theatre in Manchester.

 In 1978 she returned to London in Plenty by David Hare at the National. An early television appearance was in a commercial for Head & Shoulders shampoo. In 1982 she made her first appearance on stage in the United States as Lady Nijo, a 13th century Japanese concubine, in Top Girls by Caryl Churchill, which was reprised at The Public Theater in New York, after its creation at the Royal Court in London. She won her first award, an Obie, for her performance. The next year she took her first major role on film in Richard Eyre's Loose Connections with Stephen Rea. At the same time her television work included On Approval (1982), Reilly, Ace of Spies (1983) and Dead Head (1985).

In 1985 she joined the Royal Shakespeare Company for the production of Troilus and Cressida, in which she played Helen of Troy. The year after she created the role of the Marquise de Merteuil in Les Liaisons Dangereuses, the play by Christopher Hampton after the French novel by Choderlos de Laclos. The play opened at The Other Place in Stratford-upon-Avon, then transferred to the Ambassadors in the West End, and later to Broadway. For her performance she was nominated for a Tony and won the Olivier Award for Best Actress and a Theatre World Award. She was however replaced by Glenn Close for Dangerous Liaisons, the film adaptation of the play; similarly John Malkovitch was selected for the role of Valmont instead of Duncan's co-star Alan Rickman.

In 1988 Duncan won an Evening Standard Award for her role of Maggie in Cat on a Hot Tin Roof by Tennessee Williams. At the same time she became a regular in the plays of Harold Pinter and the television work of Alan Bleasdale and Stephen Poliakoff. She performed for a second season with the RSC in 1994–1995, in A Midsummer Night's Dream in which she played the double role of Hippolyta and Titania. 

Duncan played Servilia Caepionis in the 2005 HBO-BBC series Rome and she starred as Rose Harbinson in Starter for 10. She played Lord Longford's wife, Elizabeth, in the TV film Longford. In February 2009, she played Baroness Margaret Thatcher in Margaret. 

In November 2009, Duncan was cast as Adelaide Brooke, companion to the Doctor, in the second of the 2009 Doctor Who specials. 

Duncan played Alice's mother in Tim Burton's 2010 film Alice in Wonderland, she also starred in the original London run of Polly Stenham's play That Face at the Royal Court co-starring Matt Smith and directed by Jeremy Herrin. 

Alan Bleasdale asked for Duncan to feature in his first work for television after ten years of absence, The Sinking of the Laconia, aired on January 2011; she plays an upper-class passenger in the two-part drama based on a true story of World War II. She also played the mother of Matt Smith in the telefilm Christopher and His Kind written by Kevin Elyot after Christopher Isherwood's autobiography of the same title.

In 2012, Duncan will feature in four BBC2 productions of Shakespeare's history plays. She is to play the Duchess of York in the first film, Richard II, with David Suchet as the Duke of York and Patrick Stewart as John of Gaunt. 

Duncan was appointed Commander of the Order of the British Empire (CBE) for services to drama in the 2009 Birthday Honours.

Graeme Farmer wrote the K9 episodes Fear Itself (with Everett DeRoche), Alien Avatar and Taphony and the Time Loop (with Anthony Morris).

Peter Straker played Commander Sharrel in the Doctor Who television story Destiny of the Daleks.

Also appeared in Casualty, What's Your Name 41?, Urban Gothic, Jack and the Beanstalk, The Orchid House, Connie, Morons from Outer Space, Alicja, The Gentle Touch, Centre Play, Village Hall, Up the Chastity Belt, Girl Stroke Boy

Penelope Lee voiced the computer in the 1985 Doctor Who story Revelation of the Daleks.

Born in Wyke Regis, England, Penelope Lee has been in a diverse variety of film, television, and theater. 

She won an arts council scholarship at age 36 to study singing and went to The Aldburgh School for Advanced Students. Throughout her acting career Lee has worked continually for BBC Radio Drama. 

She was Nominated Best Actress on BBC Radio in 1978 for Away Day, a one woman play by Franz Xavier Kroetz.

Wendy Williams  is a British actress.

She played Vara in the 1975 story The Ark in Space.

She is best known for her work on television, with credits including: Danger Man, Z-Cars, The Regiment,The Pallisers, The Carnforth Practice, Thriller, Survivors,Poldark, Tenko and The Darling Buds of May. She had a long running role in Crossroads as Mrs. Banks.

She was married to Hugh David.at the time that The Ark In Space was filmed.

Segments of the biography are from Wikipedia, licensed under CC-BY-SA 

Rio Fanning played Harker in the 1977 Doctor Who serial Horror of Fang Rock.

Also worked on 13 Steps Down, Hatfields & McCoys, Days That Shook the World, Monk Dawson, Father Ted, The Steal, Priest, The Bill, Peak Practice, All Creatures Great and Small, Thin Air, Elphida, First Among Equals, Casualty, The District Nurse, Play for Today, The Old Men at the Zoo, The Agatha Christie Hour, Harry's Game, Juliet Bravo, The Gentle Touch, The Sandbaggers, Fox, Emmerdale, Blakes 7, The Onedin Line, Couples, Warship, Within These Walls, Against the Crowd, Rooms, My Old Man, Z Cars, Softly Softly: Task Force, The Brothers, Fall of Eagles, Hadleigh, ITV Playhouse, The Regiment, All Our Saturdays, The View from Daniel Pike, Budgie, ITV Sunday Night Theatre, The Adventurer, Brett, Follyfoot, Codename, The Troubleshooters, Tom Grattan's War, The Champions, The Avengers, The Jazz Age, Softly Softly, The Revenue Men, This Man Craig, Dixon of Dock Green, The Man in Room 17, No Hiding Place, No Cloak - No Dagger, Ghost Squad, The Primitives, A Prize of Arms, ITV Play of the Week, Private Investigator, Great Expectations

John Stratton  was a British actor, born in Clitheroe, Lancashire.

He is best remembered for his television credits, including: Quatermass and the Pit, Dixon of Dock Green, The Avengers, It's Dark Outside, The Man in Room 17, Public Eye, Mr. Rose, Z-Cars,The Troubleshooters, The Expert, The First Lady, UFO, Hadleigh, Softly, Softly, The Pallisers, Fall of Eagles, The Professionals, Doctor Who (in the serial The Two Doctors), Juliet Bravo, Lovejoyand Backs to the Land.

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

Derek Francis was an English comedy and character actor.

He was a regular in the Carry On film players, appearing in six of the films in the 1960s and 1970s. He appeared in Roger Corman's last film of his Edgar Allan Poe series The Tomb of Ligeia (1964). He also took roles in several BBC adaptations of Charles Dickens novels. His last role was in the 1984 version of A Christmas Carol.

Other roles included parts in the most established television series of the period: Rising Damp, The Professionals, The Sweeney, The New Avengers, Danger Man, Jason King, Up Pompeii!, Wild, Wild Women, Coronation Street, and Z-Cars. He also appeared as the Emperor Nero, a comic turn in the early Doctor Who story entitled The Romans oppositeWilliam Hartnell.

Among his stage roles was the title character in Cymbeline for the Old Vic in 1957.

He died of a heart attack in Wimbledon, London.

John Fraser is a BAFTA-nominated Scottish actor of cinema, television and theatre.

One of his earliest roles was as Inigo Jollifant in the second film version of J.B. Priestley's The Good Companions. He went on to have starring roles in films such as El Cid, The Trials of Oscar Wilde (playing Lord Alfred Douglas), and Roman Polanski's Repulsion. He is familiar on television, with guest roles in series including Danger Man (1964), Randall and Hopkirk (Deceased) (1969), Columbo (1972), Doctor Who (1981) and The Bill (1995).

Hayden Jones voiced the Autons in the Doctor Who serial Terror of the Autons and played Lenny Vosper in The Mind of Evil.

Also worked on Bergerac, Somewhere in Time, Barlow, The Pallisers, War & Peace, Softly Softly: Task Force, Z Cars, Brett, Elizabeth R, Freelance, Special Branch, Crime of Passion, Counterstrike, Public Eye, The Troubleshooters, Out of the Unknown, Redcap, Softly Softly, United!, The Wednesday Play, Swizzlewick, Smuggler's Bay, The Villains, Armchair Theatre, No Cloak - No Dagger, Jezebel ex UK, The Avengers, City Beneath the Sea, Out of This World, Three Golden Nobles, Dancers in Mourning

John Bay  was an American actor and playwright.

Bay was born in Chicago, Illinois, the location of his family's company, Bay's English Muffins.

He was married to the actress Elaine Stritch for ten years, until his death.

Bay appeared in many productions, including the Doctor Who story The Crusade in 1965, playing the fourth Earl of Leicester.