Vigil is a high pressure cop show set inside a nuclear submarine

► Vigil is available to stream on BBC iPlayer.

A cop show in a submarine. Perhaps somewhere in the history of TV sleuthery it’s been done before, but it certainly feels like a fresh inspiration. Acting as a nuclear deterrent means HMS Vigil must remain mostly under water and be circumspect about relaying messages back to shore, lest it give away its position: not ideal for a detective needing to share investigative information. Suranne Jones’s Detective Chief Inspector Silva is also recovering from a personal tragedy which involved her being trapped underwater in a car, so coping inside a tin can at considerable depth will prove a test.

Tom Edge (who wrote the 2019 biopic Judy, for which Renée Zellweger won multiple awards) created Vigil and wrote four of the six one-hour episodes: he parcels out story developments at sea and on shore very capably, shifting attention between various suspects and deftly placing moments of jeopardy and genre-compliant car chases, punch-ups and so forth. He also finds a balance between personal crisis (a protagonist learning to love again in the aftermath of consuming grief ) and the various geopolitical angles – Britain’s ageing submarine fleet, continuing micro-aggressions from Russian naval forces, and the future of the nuclear submarine base in a potentially independent Scotland.

Edge keeps all these plates spinning, making good use of a romantic connection between Jones and fellow DCI Rose Leslie, who stays on shore. Where questions of personal trust and commitment are concerned the drama is on sure ground, but it treads more warily around the wider geo-political issues, while relying on Cold War anxieties to sustain background tensions. It also tiptoes round Westminster-Holyrood frictions, avoiding mention of the party affiliation of Stephen McCole’s concerned local MP, whose opposition to the nuclear deterrent springs from an old CNDer’s anti-nuke impulse rather than an SNP-branded goal of Scottish self-determination.

It’s at the level of sustained gut-level tension that the drama succeeds best, helped by Jones’s striking ability to manifest steely determination and fraying vulnerability with equal conviction, and framed by the palpable claustrophobia of highly convincing mock-up sets for HMS Vigil. It all builds to a gasp-inducing cliff-hanger at the end of Episode 5, which is thematically consistent with the pressure-points the drama has been seeding throughout and isn’t thrown away by the start of the final instalment. It’s bound to be one of the moments of the year on UK TV.