Between 2008 and 2011 Mark was the series consultant on the BBC's BAFTA award winning series Casualty and led the core story team as well as writing multiple episodes of the show.
His personal credits include the two-parter that kicked off the relaunch of the show in September 2007 as well as Episode 25, Sex And Death, of which the The Times said that "the plotting was comparable to ER at its best."
In 2011, Eggbox, created by Mark and Tom Bidwell was commissioned for a pilot
for BBC Three with Jamie Thraves as director and produced by Hattrick. Mark was also part of the Eastenders core story team.
Before turning to television, Mark wrote for the stage. Three of his plays, Crap Dad, Scuffer and Sunbeam Terrace, were produced at West Yorkshire Playhouse.
In 2012 West Yorkshire Playhouse produced Mark's critically acclaimed adaptation of Louise Rennison's Angus, Thongs and Even More Snogging. Mark has also worked with young playwrights' groups as a tutor and mentor. In addition to this Mark has also written on the second series of Call The Midwife and new E4 drama Youngers.