Michaela Coel in I May Destroy You, BBC One

From the first 20 minutes of I May Destroy You, you wouldn’t necessarily guess that it's about sexual assault. Its title character, Arabella (Michaela Coel), is the author of a Twitter memoir titled Chronicles of a Fed-Up Millennial, and she’s now stuck in writer’s block. Story cards are taped to her bedroom wall, she writes in cabs and buses around London… everywhere except her empty office in Soho, where she endlessly procrastinates.

In between writing periods Arabella hangs out with mates, boozes, takes drugs and watches endless YouTube videos. She’s a sweet, fun-loving, unemployed Londoner, of a kind that’s easy to recognise and make friends with.

The first episode offers little in terms of direction: it’s sporadic and free (much like her), structured like a slice-of-city-life story. But towards the end, a harsh, violent memory flashes dizzily through Arabella's mind and the story turns into something more horrific, slicing through her sense of normality.

Photo: BBC/Various Artists Ltd and FALKNA/Laura Radford

Coel wrote the show, loosely based on a personal experience. She naturalistically captures Arabella's long, enduring realisation of having been assaulted, and her struggle to piece together the truth.

In the first episode, it’s hard to establish the relevance of various characters, who walk or smile or saunter through different areas in Arabella’s life. There’s one affluent couple, for example, who are arranging a threesome to spice up their love life. Although the awkward organisation has its funny moments, their connection to Arabella feels circumstantial at first.

But they’re part of Arabella’s story and, as the series continues, other characters will have their own ambiguous sex stories to tell. They arrive in dribs and drabs, often functioning to support Arabella, no doubt waiting to expand their characters within the next 10 episodes.

It transpires that Arabella's drink was spiked, and only fragments come back to her. Episode two gradually eases into this, with certain revelations sparking sharply in everyday situations like walking with a friend on a busy street. There's no sensational or overdramatic hyperbole here; Coel clearly wants to maintain as much realism as possible.

Photo: BBC/Various Artists Ltd and FALKNA/Natalie Seery

As certain details come into focus, the series catalyses into a beautifully paced investigation drama as Arabella retraces her steps from the night before. Her suspicions grow into our suspicions, but there’s no need to say them out loud in overlong explanations, as in most detective dramas. Coel builds suspense in a rawer way: one scene, in particular, has Arabella question a man who was potentially involved in her assault, and a harrowing, choking tension fills the room.

It’s hard to judge a series on the first two episodes, especially as it’s clearly meant to unfold slowly. But from what Coel has offered so far, both in her vividly natural performance and tangibly realistic writing, there’s promise from this quiet yet provocative drama. The exterior shots step into a London that's remembered fondly in lockdown, into the familiar colours of particular streets and nightclubs and restaurants – to the extent that Coel makes you believe it’s still there. We look forward to seeing more.

I May Destroy You airs on Monday 8 June and Tuesday 9 June at 10:45pm on BBC One