Vigil review: The second series of this Suranne Jones smash-hit is a silly, addictive watch

When a TV show is a massive hit, there's also pressure to serve up more of the same that made it a massive hit. The trouble is, replicating that success is a difficult thing, ruled by the law of diminishing returns.

Vigil (BBC1, Sun-Tues, 9pm) was a smash when it arrived on our screens two years ago, as Suranne Jones's DCI Amy Silva and her sidekick – and ex-lover – DI Kirsten Longacre (Rose Leslie) had to solve a case on board a nuclear submarine, and uncovered Russian spies, spooks in a peace camp and dodgy political dealings.

This new series follows much the same police procedural, with Silva and Longacre called in to investigate the apparent deadly sabotage of an armed drone trial, put on by the RAF for the benefit of potential buyers from a fictional Middle Eastern emirate, Wudyan.

I shouldn't say drone, of course, as the military types constantly remind Silva, it's really an RPAS – “a remotely-piloted air system. It's what civvies call drones”.

Suranne Jones returned as DCI Amy Silva in the new series of BBC hit drama Vigil this week (Picture: BBC/World Productions)

That's us told.

Vigil is full of these acronyms and abbreviations, designed to separate the plod from the high-flying RAF people, diligently serving British interests across the globe.

The trouble is, as Vigil is a pains to point out, these interests often collide with those of the Wudyani population, and those of neighbouring countries, with whom Wudyan is apparently at war.

The RAF bigwigs – mainly Air-Vice Marshal Marcus Grainger, played by Dougray Scott as someone so insufferably smug it's difficult to restrain yourself from punching the TV any time he appears – naturally don't seem to find anything troubling about this.

Dougray Scott played the 'insufferably smug' Air Vice-Marshall Marcus Grainger in Vigil (Picture: BBC/World Productions)

“You’re supporting Wudyan’s conflict with their neighbours?” Silva asks Grainger.

“No, that’s not how we’d put it,” he replies, splitting semantic hairs. “We supply expert operational support. It helps sustain our strategic position in the region and that’s really the most important thing.”

Meanwhile, Longacre comes across a Wudyani journalist who apparently witnessed the whole drone farrago, and has the opposing view, in case we were wondering if this was an ethically problematic area.

“Peak oil is coming,” he tells Longacre, “When the money stops, this is how the regime clings to power... these drones are the tools of oppression.”

DI Kirsten Longacre (Rose Leslie) questions a suspect in the new series of Vigil, which began on BBC1 this week (Picture: BBC/World Productions)

There are constant reminders of these grey areas, as the RAF’s technology is used to keep an eye on dissidents and arrest journalists – an on occasion, it seems, kill them.

It’s at it’s best, however, when the police investigation takes over the action. The fickle finger of blame for the drone – sorry, RPAS – attack swings rapidly from ethically compromised RAF officers, to Wudyani dissidents, to troubled teens, to traumatised war veterans to pilots hiding homosexual relationships.

Meanwhile, each episode is designed to slowly build to a shocking cliffhanger, with the shock ending of the this week’s episode leaving Silva in mortal danger.

It’s all hokum, of course, and the framing of Britain's place in the world and the morally dubious compromises we are all implicitly involved in to maintain that place are presented in a heavy-handed way, thanks to the objectionable Grainger.

But its slow-build, explosive release structure is addictive, and the revolving cavalcade of suspects keeps you guessing, every episode seeming to put three new people in the frame.

You wonder if Vigil can sustain its same military setting, murder, geopolitics and same-sex relationship plotting for a third series, without it degenerating into self-parody – those diminishing returns in effect – but for the moment it’s a silly, fun, moreish watch.