An immigration officer enters the room carrying two cups of tea. His colleague Wendy (Game of Thrones’s Lena Headey) is in the middle of an interview with a detained migrant. The camera observes as he hands her one mug, keeping the other for himself. Based on director Anthony Woodley, screenwriter Helen Kingston and producer Luke Healy’s experiences of volunteering in the Calais refugee camp, this drama notes the casual indignity with which the government treats displaced people.

The film concerns the passage of 30-year-old Haile (Ivanno Jeremiah), an Eritrean exile who has spent eight tortuous months travelling to England. We follow his experiences at sea and in the camp, but it’s the details, such as his waterlogged shoes held together with duct tape, or the fact that it takes more than half the film for someone to ask what his name is, that are most moving. Moments of obvious tragedy on the other hand, including a pregnant woman forced to watch her husband perish, feel manipulative. The film seems convinced that there is a right (and therefore wrong) kind of refugee, and that we must be personally moved by an individual case in order to understand their plight.

In its better moments it’s an effective thriller; a set piece that sees Haile smuggle himself and a Pakistani couple on to a lorry in the middle of the night is tense and well-executed, and Jeremiah’s performance is genuinely captivating, the actor’s wide eyes communicating fear, humour and a hunger to survive. “You entered the UK illegally,” says Wendy. “There’s no legal way,” he replies. The Flood wants to indict the system, but undermines itself by giving Headey’s coldly efficient immigration officer a chaotic home life (she’s seen calling her ex-husband at odd hours and swigging vodka from the bottle). Instead of complicating her character, her addiction functions to absolve her from complicity in deporting the wrong people.