Revealed – the joker who will be Cameron

For an almost unknown young comedy actor it is a part that must be beyond his wildest dreams: to play the role of David Cameron, the probable next prime minister, in a television drama documentary that has Westminster agog.

When Boris met Dave will dramatise the school and university years of the Conservative Party leader and his friend and political fellow-traveller, Boris Johnson, the Mayor of London. This period in the two Old Etonians' lives is widely known for an infamous mid-Eighties Oxford University photograph, which shows the pair posing in the blue tailcoats and mustard-coloured waistcoats of the notorious Bullingdon Club.

The 90-minute documentary will be shown on More 4 in the autumn, prompting complaints from Tory MPs that it may influence voters in the run-up to the next general election. Philip Davies, a member of the House of Commons Committee on Culture, Media and Sport, said the timing of the programme left Channel 4 open to "accusations they are pursuing an agenda".

Into this pressure cooker of a role, steps Jonny Sweet, 24, until now best known for his one-man show, Mostly About Arthur, which he is taking to the Edinburgh Fringe next month. That show features Jonny using a power point presentation and video to reminisce over his "late brother" Arthur, "a writer of blurbs on the back of books".

Like Cameron, Sweet has mid-length hair and a melodious, well-spoken voice, though he stands an inch shorter at 5ft 11in. Like Cameron, he is an Oxbridge graduate, though Sweet went to Cambridge and not Oxford. And rather than join an exclusive dining club such as the elite Bullingdon, which is famous for wild bingeing, Sweet preferred the thespian company of the famous Cambridge Footlights, where the likes of Griff Rhys Jones, Hugh Laurie, Rory McGrath and David Mitchell have cut their comedy teeth.

Television viewers may recognise Sweet from a small part he played in the cult E4 comedy The Inbetweeners, about a hapless trio of geeky sixth formers. One of the stars of that show, Joe Thomas, has been Sweet's writing partner since they met at Cambridge in 2003. Another star of The Inbetweeners, Simon Bird, (who played Will McKenzie) is also a close friend of Sweet's and a former president of Footlights. The three friends have performed on the Edinburgh Fringe as The House of Windsor.

Channel 4 has a track record in trying to dramatise the lives of modern politicians such as Tony Blair, Gordon Brown and David Blunkett. The Deal, a 2003 drama written by Peter Morgan and directed by Stephen Frears, recreated the events around the famous Granita power-sharing meal, with Michael Sheen playing Blair.

In When Boris Met Dave, the part of Boris Johnson is played by the Shropshire-born actor Christian Brassington, 26, who bizarrely played an undergraduate Tony Blair in the 2006 television drama Tony Blair: Rock Star.

Meanwhile, Diana Quick is to star in a drama documentary based on the fluctuating emotions felt by the Queen at the time of events surrounding the marriage of her eldest child, Prince Charles, to Camilla Parker-Bowles.

The actress best-known for her performance as Lady Julia Flyte in Brideshead Revisited, has been cast as the Queen. Quick, 62, is considerably younger than Her Majesty, who was 79 when the marriage took place in 2005. Camilla Parker-Bowles will be played by Joanna Van Gyseghem while Martin Turner will play Charles.

The piece will conclude the five-part series, The Queen, which portrays Her Majesty's feelings at five critical moments. Five different actresses play the monarch.