A group of "suits" occupy London’s Lancaster House for a European ambassadors’ conference. It’s one of those intense meetings where delegates sit, nominally entranced, but surreptitiously scratching their navels as their colleagues deliver scripted speeches.

The Bulgarian president is sitting next to his country’s ambassador to the UK. They share a few words, uttered in a hoarse monotonous whisper, their eyes staring blankly into the distance.

"Cut!" shouts director Dimitar Mitovski. This time he looks pleased, having extracted just the right look of glazed distraction required. Eventually, the other "suits" remove their ties and the other actors, mostly extras, are pleased to decamp outside, not, in reality, to a London street but rather to the square around Alexander Nevsky Cathedral, home to the National Gallery for Foreign Art.

Mission London, an English-language comedy shooting in Sofia this summer, tells the story of the chaos surrounding the new Bulgarian ambassador’s arrival in London. It’s based on a novel of the same name, published in 2001 by Alek Popov, relating his experiences as cultural attache in the UK.

Orlin Goranov, a 1980s pop star (one of his big hits was called "Svetat e za dvama" - The World Is For Two) plays the part of the Bulgarian president, while Ana Papadopulu is the main female lead.

Bulgarian actor Julian Vergov plays the Bulgarian ambassador. A mainstay of the Bulgarian National Theatre, Vergov has also appeared in several action movies, including the recent Val Kilmer project Fake Identity and SS Doomtrooper with the ubiquitous British villain in Sofia, Ben Cross.

Sofia has become a favourite venue for filmmakers thanks to low costs. Other recent movies filmed here - all Nu Boyana productions - include The Code with Morgan Freeman, the Black Dahlia with Scarlett Johansson and several Dolph Lundgren action vehicles.