Former League of Gentlemen actor once said he gave Mycroft Holmes ‘reptilian and Mandelsonian’ qualities

Sherlock star and co-creator Mark Gatiss is to play Peter Mandelson, the spin doctor during the New Labour era in a TV drama based on the back room deals that led to the coalition government in 2010.

The one-off Channel 4 drama, Coalition, aims to portray the “astonishing rise” of deputy prime minister Nick Clegg, a “rank outsider” who “would decide the fate of the country”.

Gatiss would seem perfectly placed for the role of Mandelson, known to enemies and friends alike as the “prince of darkness”. He drew inspiration from the politician credited with rebranding the Labour party for the part of Mycroft Holmes, Sherlock’s brother, who secretly runs the government in the hit series, once saying he imbued the character with “reptilian and Mandelsonian” qualities.

Bertie Carvel, who won several awards for his performance as Miss Trunchbull in the stage adaptation of Roald Dahl’s Matilda, is cast as the Liberal Democrat leader Nick Clegg. Mark Dexter, of The Bletchley Circle and Ripper Street, plays David Cameron, and Ian Grieve takes on the role of Gordon Brown, a part he has already taken on in the play The Confessions of Gordon Brown.

Channel 4 said the drama, due to be aired in 2015, will deliver “penetrating insight into one of the most influential and significant political decisions of recent years”.

Written by playwright James Graham, whose political play This House, set at the end of James Callaghan’s Labour government, was a hit at the National Theatre, Coalition “charts the emotional wrought, politically charged and often frenzied moments which led to Nick Clegg’s astonishing rise from rank outsider to the man who would decide the fate of the country”.

Graham told the Sunday Times: “As with many of the parts Gatiss has played, there is that slight darkness, slight edge that Mandelson has. But he also has the capacity for that three-dimensional pathos. We also need to avoid Mandelson descending into the stereotype”.