Question: Emilia Rose Elizabeth Fox, is an English actress, known for her role as Dr. Nikki Alexander on BBC crime drama "Silent Witness", having joined the cast in 2004 following the departure of which Northern Irish actress, well known for her television roles, including Heather Black in the Channel 4 soap opera "Brookside"?
Context: Amanda Burton (born 10 October 1956) is a Northern Irish actress, well known for her television roles, including Heather Black in the Channel 4 soap opera "Brookside", Beth Glover in "Peak Practice", Sam Ryan in the BBC crime drama series "Silent Witness", Clare Blake in "The Commander" and Karen Fisher in "Waterloo Road". Silent Witness is a British television crime drama series, produced by the BBC, which focuses on a team of forensic pathology experts and their investigations into various crimes.  First broadcast in 1996, the series was created by Nigel McCrery, a former murder squad detective based in Nottingham.  He later went on to create the hit series "New Tricks", with writer Roy Mitchell.  Since 1996, twenty series of the programme have been broadcast.  Amanda Burton originally starred as primary character Dr. Sam Ryan, before leaving the show during the eighth series.  Since, the series has featured more of an ensemble cast, currently consisting of Emilia Fox, David Caves, Liz Carr and Richard Lintern.  The programme is broadcast in more than 235 territories, including ABC in Australia, Showcase and the Knowledge Network in Canada, KRO in the Netherlands, TV One and Prime in New Zealand, and BBC America in the United States.  Twenty years after its inception, "Silent Witness" continues to achieve good audience ratings; in 2011 Series 14 attracted an average audience of nine million viewers. Heather Black ("née" Haversham; previously Huntington) was a regular character in UK Channel 4 soap opera, "Brookside", played by Amanda Burton from 1982 until 1986. Hollyoaks is a British soap opera, first broadcast on Channel 4 on 23 October 1995.  It was originally devised by Phil Redmond, who had previously conceived the Channel 4 soap "Brookside".  The programme is set in a fictional suburb of Chester called Hollyoaks, and features a large cast of characters primarily aged between 16 and 35.  It is mostly filmed and produced in Childwall, Liverpool, although nearby locations are sometimes used.  Beginning with a cast of just seven major characters in 1995, the serial now has approximately 50 main cast members.  "Hollyoaks" has a high cast turnover in comparison with other British soaps; as of May 2014, just thirty-seven characters have spent five years or longer on the show.  The programme has won 28 British Soap Awards, 11 Inside Soap Awards, one "TRIC Award" and one National Television Award; at the 2014 British Soap Awards, "Hollyoaks" won Best British Soap for the first time, breaking the 15-year draw between rival soaps "EastEnders" and "Coronation Street".  It is also popular around the world.  The longest-serving cast member is Nick Pickard, who has played Tony Hutchinson since the first episode in 1995; all the other original characters left before 2000. "Silent Witness" is a British television drama.  The following is a list of all episodes that have been broadcast across all television series, since the series began on 21 February 1996.  The first seven series featured Amanda Burton in the lead role.  Following Burton's departure (in series 8, episode 2), Emilia Fox joined the show (in series 8, episode 5) as new forensic pathologist Nikki Alexander, and as of 2016 she is still in the series.  In the first episode of series 6, William Gaminara and Tom Ward both joined the series.  After series 15, Ward left the show to pursue other projects.  He was replaced by David Caves and Liz Carr who both joined the show in series 16. Emilia Rose Elizabeth Fox (born 31 July 1974) is an English actress, known for her role as Dr. Nikki Alexander on BBC crime drama "Silent Witness", having joined the cast in 2004 following the departure of Amanda Burton.  Fox is now the longest serving cast member since the departures of Tom Ward in 2012 and William Gaminara in 2013.  She also appeared as Morgause in the BBC’s "Merlin" beginning in the programme's second series.  She was educated at Bryanston School in Blandford, Dorset. Sue Johnston OBE (born Susan Wright; born 7 December 1943) is an English actress known for playing Sheila Grant in the Channel 4 soap opera "Brookside" (1982–1990), Barbara Royle in the BBC comedy "The Royle Family" (1998–2012), Grace Foley in the BBC drama "Waking the Dead" (2000–2011), Gloria Price in the ITV soap opera "Coronation Street" (2012–2014) and Miss Denker in the ITV drama "Downton Abbey" (2014–2015).  She won the 2000 British Comedy Award for Best TV Comedy Actress and was nominated for the 2000 BAFTA TV Award for Best Comedy Performance for "The Royle Family". Bronagh Waugh (born 6 October 1982) is a Northern Irish actress best known for playing the character of Cheryl Brady in the Channel 4 soap opera "Hollyoaks" as well as appearing on "T4 On The Beach" as herself.  She appeared as an extra for "Doctor Who".  She also played Sally Ann Spector on the BBC series "The Fall". Nicola "Nikki" Shadwick is a character in Channel 4 soap "Brookside" played by Suzanne Collins from 27 March 1998 until the programme's final episode on 4 November 2003.  Nikki's storylines have included being "date-raped" by Luke Musgrove at a party at Number 5, hosted by Leo Johnson and Tim O'Leary.  Not long after this ordeal, Nikki had to deal with the deaths of her father Greg and Brother Jason after an explosion on Brookside Parade, and was also stalked by an obsessive friend at her University.  Her younger sister Emily was killed during the Brookside Siege of 2002 and her mother then moved to Brussels.  In the final episode of Brookside Nikki reveals she is going to live with her Mother Margi in Brussels. Carli Jo Norris (born 23 June 1974) is an English actress, known for her role as Anoushka Flynn in the BBC soap opera "Doctors", in the BBC soap opera "EastEnders" as Belinda Peacock (nee Slater), as Martha Kane in the Channel 4 soap opera "Hollyoaks" and Fran Reynolds in "Holby City".  She also made a return to "EastEnders" in 2016, playing the role of Belinda Peacock, taking over from Leanne Lakey.  Norris returned to "Holby City" for a guest stint as Fran from 16 May 2017.
Answer: Amanda Burton