Mark and Steven Moffat had been talking about making a drama on Sherlock Holmes for years, but it was Sue Vertue (Steven's wife) who made them sit down and create the drama "Sherlock".
January 2009, Mark narrated the radio play Hide and Seek which was broadcaster on BBC Radio 7. It was written by Mike Carey.
In 2008, Mark gave a talk about his book Black Butterfly at The Abertoir Film Festival. The Welsh festival is dedicated mainly to Horror movies.
Mark has written for Big Finish's Doctor Who audios, his contributions include Phastasmagoria with the 5th Doctor Peter Davison and Invaders from Mars with the 8th Doctor Paul McGann.
Mark's Doctor Who books include: St. Anthony's Fire (1992), Nightshade (1993) which is available on the official Doctor Who site for download, The Roundheads (1997) and Last of the Gaderene (2000).
Both of Mark's parents worked in a psychiatric hospital. Mark's job in his first year of college was as a gardener in it.
In the 2007 Independent on Sunday's annual Pink List - the Top 100 powerful and influential and openly gay - Mark was a new entry at No. 80. He does not appear in the 2008 list.
Mark used to write for the "Doctor Who Magazine" under the pseudonym 'Sam Kisgart,' which is an anagram of 'Mark Gatiss.' He later played a character of the same name in the Doctor Who Unbound play, Sympathy for the Devil.
Ian Bass - Mark's partner - did the art for the graphic novelisation of Mark's book, The Vesuvius Club.
In 2006, the University of Huddersfield awarded Mark an Honorary Doctorate of Letters.
Mark's first Lucifer Box novel, The Vesuvius Club, brought him a best newcomer nomination in the 2006 British Book Awards. The series is now up to three books after The Vesuvius Club, the second book title is The Devil in Amber and the third is The Black Butterfly.
In April 2007, it was announced that the BBC are to make Mark's first Lucifer Box novel, "The Vesuvius Club", into a TV drama.
All 3 appeared in episodes of Doctor Who.
Mark has installed a fully equipped Victorian laboratory in his North London home, which stems from a boyhood dream.
(On the inspiration for his show, Crooked House stemming from a mask he bought)
Mark: The third story, which is about the doorknocker itself. I bought a Maori death mask in Paris a few years ago. I bought it because A Christmas Carol is my favourite story and it looked the way you would imagine Jacob Marley's face when it appeared in the doorknocker. I'm not a superstitious person, but it just felt wrong. It was hanging on the wall until one day we were woken by a large bang and I went downstairs and it was lying in the middle of the room. It was probably heavy traffic, whatever, and I thought 'well, this wants to go home'. So I rang the New Zealand Embassy and went down to see them and said 'look, I've got this thing. I don't think it should ever have left and in fact I think it might want to go home'. So I gave it to them.
(On the works of Sir Arthur Conan Doyle who he based his new drama "Sherlock" on)
Mark: The fact that Steven (Moffat), myself and millions of others are still addicted to Conan Doyle's brilliant stories is testament to their indestructibility. They're as vital, lurid, thrilling and wonderful as they ever were.
(Discussing if there will be some new "A League of Gentlemen" project in the future)
Mark: We would love to do something together again but we were together for 12 years almost constantly. We wanted a proper break and to do something else. I would never say never because I would love to but everything has its season... or three seasons.
(On his earliest television memory, an episode from the original "Doctor Who")
Mark: I can still remember being terrified by an episode called The Daemons, in which this gargoyle came to life. They filmed it in a documentary style with captions. I actually thought Doctor Who had become real. That one upset me the most.
(On adapting the Agatha Christie's Poirot novel "Cat Among the Pigeon" for television)
Mark: When I was asked if I might consider adapting one, it was like pushing on an open door. It's been a sheer delight and I know that, in David's (Suchet) exceptional Poirot, my script is in the very best hands.
(Answering a question asking if he would like to take over as producer of "Doctor Who" at some point)
Mark: I don't think so. I worship the programme - I've given most of my life to it and several pints of my blood! It's really a very good thing to be slightly more detached and just to contribute as I am with a script and appearing in it like that. I couldn't be happier. It's such an extraordinary response and for Russell to have pulled it off so brilliantly...who would have thought a couple of years ago? And it's more popular than it's ever been, that's the most amazing thing.
(On which "Doctor Who" villain from the classic series, he would like to come back)
Mark: You know, I love the fact that the Macra came back the other week. It was such a thrill, I felt like a child, it was like 'Fuck, it's forty years on'! Brilliant. I really like the fact that they're being quite careful with that. The Macra's not like a big baddie - obviously the Daleks and Cybermen need to come back and I would like the Ice Warriors. I think, for myself, I'd most like the Yeti to come back.
(About the three Lucifer Box's books jumping several decades)
Mark: I finished The Vesuvius Club, I just had an idea in the bath, as I usually do - it's the only place I have ideas. I'm not sure if it's been done before. Flashman goes through the ages, but actually to do three definite jumps like that... as soon as I had the idea I just thought it was a very interesting framework, to look at a character who in the first one is almost arrogantly, smugly self-confident, and then suddenly to pull the rug from under him - he's old, he's got people snapping at his heels, he's got an unsympathetic new boss.
(On the character of Lucifer Box, the hero of Mark's series of books)
Mark: He has to be a bit of a rotter, but not a complete shit.
(He's) on the side of the angels, he's terribly vain and quite callous, but he's fun and you can't help but like him. It's a definite decision for him not to be too nice; that just gets in the way.
(On Christopher Eccleston as the ninth Doctor and Russell T Davies)
Mark: I think Chris makes a great Doctor, and they're both clearly men having fun. But that's what Russell said from the start - whatever he's up to, whatever danger he's in, the Doctor's having a good time.
(On the episode he wrote for "Doctor Who" first series "The Unquiet Dead")
Mark: The original idea came from Russell T Davies, but it was ideal for me - a Victorian ghost story set at Christmas with dead coming back to life! I've always had this thing about possession. Alan Bennett once said that we all have only a few beans in the tin to rattle, and I do tend to keep coming back to the idea of things being possessed. They're always my favourite kind of stories and it really must scare me on some basic level, the concept of being occupied by other entities.
(On the popularity of "Doctor Who")
Mark: Doctor Who is cool again. That's great news.
(On how where he lived as a child developped his need for escapism)
Mark: Newton Aycliffe, where I went to comprehensive, was a postwar town and I hated it. I used to wish I had been brought up in Oxford or somewhere pretty. I retreated into Sherlock Holmes. I wanted to live like an 1895 detective, not in a grim post-industrial town.
(on how he felt about appearing in "Doctor Who" for the first time")
Mark: It was beyond exciting. I didn't know what to do. I didn't sleep at all the day I got the call. I thought, 'This is exactly how I imagined it would always be'. I was so excited - I couldn't stop thinking about it. Thank God, it's everything I hoped for: a brilliant part, great script, a proper meaty baddie role, so I was just delighted.
(on writing an episode of the re-imagined "Randall and Hopkirk Deceased")
Mark: Maybe it's too rich a brew. I don't know. We were afraid that it wouldn't be enough but now maybe it's too much! You really want to have a main plot and a subplot, but if they're too grandiose, the storylines end up fighting each other. That may be slightly the case with ours, I'm not sure. Better that than a rather bland and basic detective story.
(on filming "The League of Gentlemen" film)
Mark: There was a funny moment when we were filming by the sea and the doubles for Tubbs and Edward and Papa Lazarou were all having a fag. Actually, I filmed it because it was really quite creepy.
(on appearing in an episode of "Doctor Who", "The Lazarus Experiment")
Mark: And yet there were a couple of moments when I just became totally overwhelmed with the whole thing. At one point I was crouched inside my machine, and every time the door opens all this smoke billows out, and there's me in my tuxedo and the smoke starts rising over my head and I just sort of burst out through the door and it was like, 'Bloody hell! I'm in Doctor Who! Yes!'
(on his feelings on the new series of "Doctor Who")
Mark: It's extraordinary, but I've always carried in my heart a version of how I thought it should be, and it's this one. It's a new show, not one addressing a dwindling bunch of "Doctor Who" diehards like me, but a modern show for a new audience.
(on his second story for the new series of "Doctor Who", "The Idiot's Lantern").
Mark: I was a TV-obsessed child, and I'm so excited about this story because I was able to write about early TV and Alexandra Palace and the whole Quatermass ethos.
(on receiving his first book in print)
Mark: I sat there staring at it because it had my name on it, willing more to come out of it.