As Jed Mercurio’s Bodyguard hits its midway point, the pace is starting to lag, but are Richard Madden and Keeley Hawes enough to keep the series watchable?

That’s right, everyone. The Home Secretary really doesn’t care if you’re looking up b-o-o-b-s, but she does care if you’re looking up b-o-m-b-s. That’s a crucial difference and one that Julia Montague stresses shortly before she’s sent several feet in the air by a b-o-m-b.

Bodyguard’s third episode, and its midpoint (not its finale – it’s my fault for thinking Jed Mercurio could tie all this up in just three hours), is essentially one long build-up to Julia’s literally deadly speech. The first episode opened with a mini white-knuckle thriller straight out of a Liam Neeson blockbuster while the second episode punctured any longueurs with a gripping assassination attempt on Julia.

Setting such a dangerous precedent has the audience on constant edge as David attempts to protect Julia from any further attacks. Every time the pair round a corner it’s difficult not to flinch watching the screen – such is the extent Mercurio has us wound up.

It’s disappointing that aside from the events in the last five minutes, Bodyguard has settled into a pattern fairly unbecoming of a thriller that started off as viscerally as this one. Having Julia conduct a bunch of sketchy meetings then switch between her and David having sex and David being pushed by his superiors to spy on the Home Secretary is fairly routine at this point. While the atmosphere continues to tauten, there’s little in the way of practical development aside from Julia somewhat clumsily leaping on a leadership challenge in the last few minutes, and that’s not ideal.

There is the continual disintegration of David’s mental stability, as he outright throttles Julia when she tries to wake him up for some more bodyguard-on-Home-Secretary bonking. Madden plays Budd to perfection, his efficient, workmanlike nods and grunts suddenly taking on a sinister, gimlet-eyed glaze as he turns into a PTSD-riddled Terminator. It’s the perfect role for Madden and lines like his room service quip still allow him to exhibit some of the charisma that made him so compelling in Game of Thrones and Cinderella.

Hawes is characteristically strong here but it’s clear that we are just seeing the tip of the iceberg. Bodyguard has three episodes left and seeing a loved-up Julia and David is particularly unsettling. The Home Secretary clearly has a sinister agenda of national import, and it’s clearly going to reveal itself in later episodes so for now we need to enjoy this side of Julia, which Hawes, as I say, totally nails. She’s arrogant, sharp-tongued yet there’s something curiously admirable about Julia Montague that would never extend to real world politicians. Keeley Hawes is the beating heart of the Home Secretary; in lesser hands she would be a loathsome presence.

I’ve already discussed how nightmarishly taut Julia’s climactic speech is, but everyone involved should be proud of what they achieved here. From Thomas Vincent’s direction to the fake-out of the protesters to Tahir lurking around outside, everything is engineered to leave you breathless and it works.

One other fake-out that I suspect will be revealed later is that when Tahir showed David the insides of his suitcase, we didn’t actually get a look at it. David just said, “OK”, and let Tahir on his way, so it seems likely that he saw the bomb inside the case and allowed him to go through with the explosion.

While that’s probably the case it still doesn’t answer the question of whether Julia also planned this attack as well. If she did, how did she guarantee her safety and if she didn’t, is she alive? My guess is that Julia will almost certainly be fighting fit by the start of next week’s episode but what a terrific place to leave the series at its midpoint.

None of this is to say that Bodyguard isn’t good; it remains a rollicking hour of television, and Keeley Hawes is always a joy to watch but this episode seemed entirely constructed around another attack on Julia’s life. Mercurio is one of the smartest writers working in TV today so I have no doubts this is part of a wider endgame for both him and Julia but it’s hard not to feel a little let down.

Still, when the production value is this good, the performances this solid and the tension leaving viewers on a knife-edge, it’s difficult not to be swept up in the ride.

Bodyguard continues next Sunday on BBC One at 9pm.