A mishap on the Severn Bridge causes the SUV to plunge into the water, where the team picks up a mysterious distress signal. After pulling some strings with the US government, Jack secures a place on board the USS Calvin, and leads Gwen and Ianto on an expedition into the Mariana Trench, the deepest part of the Pacific Ocean.

Florence Angela L. Hoath(born 12 July 1984 in London) is a British actress best known for her 2005 appearances as Nancy in Doctor Who.

The daughter of British actress Tina Martin, Hoath made her film debut in the 1993 screen adaptation of Secret Rapture at the age of eight. Since then she has starred in a number of film and television productions, including the 2005 Doctor Who episodes "The Empty Child" and "The Doctor Dances". Also in that year, Hoath was cast to play the regular role of George Fitzgerald in Channel 5's daytime soap Family Affairs, but the show was cancelled weeks after her introduction, the final episode being broadcast in December 2005.

Biography from the wikipedia article, licensed under CC-BY-SA

Tom Price is a British actor, voice over artist and stand up comedian, who had a regular role as Andy Davidson in Torchwood.

His first TV appearance was playing a waiter in an Episode of Absolute Power. In 2008 he starred in the BBC Three sketch show The Wrong Door and filmed the role of Darrin Stephens in a pilot UK remake of Bewitched. Other TV appearances include Doctors(2009) and Secret Diary of a Call Girl (2010).

Price appeared as Gordon, a young drunken doctor, in the BBC Radio 4 comedy show Rigor Mortis for three series.

He often works as a standup comedian in and around London. He was in the final of the Daily Telegraph Open Mic award in 2001. He was one of the faces of Destination Three, and he presented Senseless on MTV.

Sara Griffiths  is an English actress

She appeared as Ray in the 1987 Doctor Who story Delta and the Bannermen and was considered as a companion to the Doctor, a role subsequently taken by Sophie Aldred.

She has appeared in many British television series including The Chief, Gentlemen & Players, Ruth Rendell Movies, Van der Valk, Emmerdale, Holby City, The Bill and Doctors. 

In 2006 she appeared in the Big Finish Doctor Who play I.D, alongside 6th Doctor Colin Baker. 

She appeared in the West End in Inspector Calls, spent a year at the Royal National Theatre & has done numerous productions on tour, abroad and in the UK. 

Richard Herring is a British comedian and writer, whose early work includes the double-act, Lee and Herring. 

He is described by the British Theatre Guide as "one of the leading hidden masters of modern British comedy". He has written and performed in a body of live one-man comedy shows including the acclaimed Talking Cock and the resulting book of the same name. He has also collaborated with the broadcaster Andrew Collins, initially on the radio series Banter, then on Collins' BBC Radio 6 Music show and on The Collings and Herrin Podcast.

During the 2000s, Herring toured with a new stand-up show almost every year. His 2010 show Christ on a Bike: The Second Coming received several 4- and 5-star reviews. It was the subject of protests from Christians in Glasgow and Lowestoft.

Tamsin Greig is an English actress principally known for two Channel 4 television comedy parts: Fran Katzenjammer in Black Books and Dr. Caroline Todd in Green Wing.

She played the Nurse in the 2005 Doctor Who story The Long Game.

 Other notable roles include Alice Chenery in BBC One's comedy drama Love Soup, Debbie Aldridge in BBC Radio 4's soap opera The Archers, Miss Bates in the 2009 BBC version of Jane Austen's Emma, Beverly Lincoln in transatlantic sitcom Episodes and Jackie in the Channel 4 sitcom Friday Night Dinner.

Everett De Roche is an American born screenwriter who has worked extensively in Australian film and TV.

He worked on the K9 series

Stunt coordinator for The Christmas Invasion; New Earth; School Reunion.

Also worked on Life on Mars, Foyle's War, Silent Witness, The Kindness of Strangers, Hustle, Judge John Deed, Jericho, Festival, Shoebox Zoo, Rose and Maloney, Cutting It, Murder City, England Expects, Winter Solstice, The Royal, Trial & Retribution, The Planman, The Commander, State of Mind, My Uncle Silas II, My Uncle Silas, Bait, Still Game, Al's Lads, Paradise Heights, The Bill, Footballers' Wives, Night Flight, Sentinels of Darkness, Linda Green, Large, Vacuuming Completely Nude in Paradise, Take Me, High Heels and Low Lifes, Bridget Jones's Diary, Intimacy, Mind Games, Complicity, Circus, Grange Hill, CI5: The New Professionals, Doomwatch: Winter Angel, Whatever Happened to Harold Smith?, Dangerfield, Smack the Pony, Peak Practice, Far from the Madding Crowd, The Ebb-Tide, Spice World, A Dance to the Music of Time, Bring Me the Head of Mavis Davis, Twin Town, Indian Summer, Prime Suspect 5: Errors of Judgement, The Leading Man, Crimetime, When Saturday Comes, The Near Room, A Mind to Murder, Cracker, Seaforth, Finney, Grushko, Earthfasts, Soldier Soldier, The Hawk, Body & Soul, Lovejoy, Frankenstein, Ruth Rendell Mysteries, Underbelly, Boon, Screen One, Prime Suspect, Medics, Life Is Sweet, Jekyll & Hyde, Tank Malling, Saracen, Children's Ward, My Left Foot, The Lion, the Witch, & the Wardrobe

Brian Cant  is an English actor,television presenter and writer best know for his work on BBC children's programmes from the 1960s to the 1980s, including Play School, Play Away, Trumpton, Chigley, Camberwick Green and Bric-A-Brac. 

He appeared in two Doctor Who stories playing Kurt Gantry in The Nightmare Begins and Tensa in The Dominators

Born in Ipswich, he was performing in drama-based BBC TV Schools Programmes about the Romans when he heard that auditions were being held for Play School. He was cast as a presenter and first appeared on the third week in May 1964, and stayed with the programme for twenty-one years and appearing on the weekend spin off Play Away.

Aside from his work on children's television, Cant is also an established actor. He was one of the guest presenters used in the 1982 series of the game show It's a Knockout after Eddie Waring retired.

On 28 November 2010 Cant received the special award at the Children's BAFTAs for his work in children's television.

Peter Cellier is an English actor who has appeared in film, stage and television. He is perhaps best known for his role as Sir Frank Gordon in Yes Minister and then Yes, Prime Minister in the 1980s.

On television, Cellier has appeared in a wide range of programmes since 1955, including detective series such as Softly, Softly, and Bergerac, historical dramas such as The Six Wives of Henry VIII, Upstairs, Downstairs and The Duchess of Duke Street.

Frank Windsor is an English actor, best know for his role as Detective Sergeant John Watt in Z-Cars and its spin-off Softly, Softly: Taskforce.

He played two character in Doctor Who in the 1980's appearing in The King's Demons and Ghost Light.

He began his career on radio and made an appearance in a 1953 film of Henry V. His first TV appearances were in 1960 in a series of Shakespearean plays.

In 1969 he appeared in the pilot episode of Randall and Hopkirk (Deceased) in the episode My Late Lamented Friend and Partner as the wealthy businessman Sorrensen with a murderous streak. 

He has also had regular roles in the BBC drama Casualty and the ITV drama Peak Practice; played Major Charlie Grace in EastEnders (1992) had various stage roles, and in his later years appeared in a number of television commercials advertising life-assurance policies for the over-50s.

John Nettleton (born London) is an English actor.

One of his most notable roles was that of Sir Arnold Robinson, the Cabinet Secretary in Yes Minister (1980-1984) and President of the Campaign for Freedom of Information in the follow-upYes, Prime Minister (1985�1988). Another political role for Nettleton was a Conservative PartyMember of Parliament in the sitcom The New Statesman.

He played the Reverend Ernest Matthews in the Doctor Who serial Ghost Light (1989), 

Other roles were in A Man for All Seasons (1966), a police sergeant in Please Sir! in 1969, theBrian Clemens thriller And Soon the Darkness (1970), Elizabeth R (1971), Black Beauty (1971), a Detective Superintendent in Doctor at Large in 1971, Upstairs Downstairs (1972), The Country Wife (1977), The Flame Trees of Thika (1981), The Citadel (1983), Martin Luther, Heretic (1983),Brass (1983), East of Ipswich (1987), Jinnah (1998), Longitude (2000), Midsomer Murders (2005), and Kingdom (2008).

On stage, he has appeared in the Lyttelton Theatre of the Royal National Theatre in the 2006 productions of Harley Granville Barker's The Voysey Inheritance, directed by Peter Gill. He also voices Grandpa in the PC Game, "The Scruffs".

To a generation who grew up as children in the 1960s and 1970s, who were viewers of the long-running B.B.C. television programme, Blue Peter, John Nettleton's voice is immediately recognised as the reader of various illustrated stories, often about historical figures, such as Florence Nightingale.

He is married to actress Deirdre Doone.

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

Grams Operator

Flemyng directed a number of episodes from fantasy series, including The Avengers, The Saint, The Baron, detective series such as Bergerac, Taggart and The Bill, and other popular drama including Minder, Lovejoy and Emmerdale. He also produced as well as directed his last job, Ellington

The actor Jason Flemying is his son.