8 questions we have after that EXPLOSIVE episode of Bodyguard

But like with Line of Duty, the motives of Mercurio's characters are murky – and as the dust settled, we were left with plenty more questions than answers. Read on for a breakdown of what might – or might not – have just happened...

1. Does Julia Montague survive?

It's the big question and one that was left hanging in the air in the episode's closing minutes – after the bomb had been detonated. With media reporting a lack of information on the Home Secretary's condition – and her eponymous bodyguard David Budd (Richard Madden) looking overwhelmed in a hospital waiting room – 'Lavendar's' status remained unclear. What we do know is she was shown moving her head on stage in the moments after the explosion took place.

Now, you might question whether a high profile drama would kill off one if its two principals mid-series, but you would do well to remember that Jed Mercurio has form. The Line of Duty creator is known to be almost as cavalier as Game of Thrones writer George RR Martin when it comes to the fates of his series leads (as viewers of LoD series two and three will know all too well). It would not be beyond the realm of possibility for the series to re-angle itself into a whodunit tracking down the perpetrators of the attack that killed the Home Secretary. Which leads us to...

2. Who was behind the bomb?

There's no question the Home Secretary was a target, thanks to her controversial views, political ambitions and bid to get security services extra surveillance powers. Which mean there are a number of parties who might be responsible for the attack.

Chief among them is Julia's new PR advisor Tahir Mahmood. His motive is unclear, but of everyone he was exhibiting the fishiest behaviour in the moments before the blast, hovering outside the auditorium with a briefcase that he was very reluctant to open. When he did so at David's request, the two shared a loaded moment which suggested there were no research papers inside, as Tahir had claimed. But was it a bomb instead? He'd encouraged her to carry out her controversial speech, but was it Tahir who emerged off stage seconds before the detonation took place? And – critically – did David see an explosive device inside and authorise Tahir's access to St Matthews?

The PR advisor had accepted a suspicious phonecall in the moments before Julia's speech began...

... before footage cut to David on his phone.

Do the two know each other? It remains unclear.

Of course, there are other suspects. Members of the security services, the police and cabinet were all seen expressing concern at Julia's political intentions, with several agreeing on the need to make a "plan".

There's also the mysterious terrorist cell who planted the bomb on the train and blew apart the road outside David's kids' school. Could they be responsible?

3. When will the police identify sniper Andy and how soon before they connect him with David?

With an e-fit in circulation, it seems like the net is closing in on David Budd. After all, how long does it take to identify a sniper with some pretty distinguishable facial scarring? And once the cops put two and two together and come up with Afghanistan veteran Andy Apstead, surely it won't take much to connect him to David and discredit the bodyguard's account of their exchange on the roof of Pascoe House.

David appeared unaware of his old friend's plot to assassinate Julia – but it's going to be hard selling that line to his new boss. And the police.

4. How are the terrorist attacks linked?

We know that the device uncovered on the train in episode one matches the one detonated outside the school in episode two. And chances are they match the bomb that blew threw St Matthews. But how are they all connected? Presumably the same cell has masterminded each one, but who is their contact on the inside tipping them off with Julia's schedule and details of her protection? And if we work on the assumption that the latest bomb is also their doing, does it rule out David's involvement, given that he would never target his children's school?

And – finally – was Andy acting as a lone wolf? Or, as Met Police chief Anne Sampson suggests, did he have an accomplice?

5. Who is the police leak?

Someone is feeding details of Julia's movements to an external party – presumably an insider who's involved in plots to do her harm. But who is it? MI-5 boss Stephen Hunter-Dunn reckons it's a police source leaking information on David's family and Julia's itinerary which feeds into the latter's suspicion of Anne Sampson. But as we know, Hunter-Dunn has an agenda rooted in discrediting the police and claiming more powers for himself and his own officers.

6. What is "the material" on Julia's secret tablet and who is "Richard Longcross"?

Earlier in the episode we saw Hunter-Dunn arrange for the delivery of some confidential information to Julia – information that was to be kept secret from the police and her own Counter Terrorism minister Mike Travis. The man who delivered it – on a tablet – operated under the pseudonym Richard Longcross and was later seen chatting to Hunter-Dunn. But as David came to realise, his real identity remains a mystery. As does the contents of the tablet...

As viewers we were gifted the odd glimpse – it held details of an individual with no history of mental illness but a dependency on alcohol and a daily cocaine addiction. And an account of sexual assault, with a witness statement which appears to come from an individual named Charlotte Foxfield. Was it incrimination evidence about a rival? For now, we're left in the dark. But David later got his eyes on the tablet and its secrets and looked pretty horrified, choosing not to report it to his superior officer when questioned. Take from that what you will.

7. Why did Julia go to Chequers?

Much was made of Julia's covert trip to the prime minister's out of town residence. What was she plotting? And what was in that confidential file she took with her? Did it contain the evidence on the tablet, designed to oust the prime minister? Despite her best efforts, details of her "ambush" leaked from the PM to members of cabinet and the security services. "Julia's snatching the key to Number 10, we need to do something fast," barked chief whip Roger Penhaligon.

8. Will David remain Julia's Bodyguard?

It's the central relationship from which the series has spiralled. But episode three saw Julia inform David that she no longer wanted him to protect her. No, it doesn't appear to be triggered by the moment he held her in a chokehold in his sleep. Instead, the Home Sec told him she she had been aware of the threat to his children's school – and then added: "I want you right beside me not because it's your job but because it's our choice".

The conversation was never resolved but, should Julia survive, will David continue to work as her protection officer?

Bodyguard continues next Sunday at 9pm on BBC1