Skyfall star Rory Kinnear and The Crown’s John Heffernan have joined Benedict Cumberbatch-fronted drama Brexit (w/t) as the first image of the Sherlock star, without his long locks, has been unveiled.

Filming has begun on the two-hour drama special, produced by Tessa Ross and Juliette Howell’s House Productions for Channel 4.

Kinnear, who has also starred in The Imitation Game and Black Mirror stars as Craig Oliver, Prime Minister David Cameron’s Director of Communications, who was brought in to oversee the Remain campaign’s communications strategy, while Heffernan, who played John Grigg, 2nd Baron Altrincham in Netflix’s royal drama, stars as Matthew Elliott, political lobbyist and Chief Executive of Vote Leave.

They join Cumberbatch, who stars as Dominic Cummings, the leading strategist and Campaign Director of Vote Leave.

Elsewhere, Call The Midwife star Liz White plays Mary Wakefield, a journalist and Dominic Cummings’ wife; The Hollow Crown’s Kyle Soller plays Zack Massingham, founder of data technology and digital marketing company AggregateIQ, which received several millions of pounds from Vote Leave to help target voters through social media advertising campaigns. Outlander’s Lee Boardman is controversial businessman and UKIP donor Aaron Banks and Bring Up the Bodies’ Nicholas Day plays Labour supporting businessman John Mills, who was another prominent donor to the Leave campaign.

Richard Goulding (The Windsors) stars as Boris Johnson, Oliver Maltman (The Crown) as Michael Gove and Paul Ryan (The Five) as Nigel Farage.

The political thriller, which will unpack the anatomy of the historic, high-stakes campaign to win the hearts and minds of the British people, is written by playwright James Graham, best known for political plays such as The Vote and the recent Who Wants To Be A Millionaire? play Quiz. It is directed by Black Mirror’s Toby Haynes. The producer is Lynn Horsford (Philip K Dick’s Electric Dreams) and executive producers are Ross and Howell. Brexit (w/t) is distributed globally by BBC Studios.