BBC thriller Bodyguard has captured the imagination of the nation: just who DID kill Julia Montague? Here's a glimpse of what we can look forward to in Sunday's last episode plus all the questions we have for the finale.

There's just one more episode for Bodyguard's David Budd to find the answers behind the death of his client Julia Montague – so ahead of Sunday's 75-minute episode, here are the questions which need to be answered for us all to have the closure we need. Amen.

The thriller has been the show of the year and offered the highest ratings for any new British drama since 2006, proving that writer Jed Mecurio is a master of his genre, a craftsman able to drop tiny clues and hints through his work which are all swept together at the climax (AND he was a former hospital doctor and Royal Air Force officer – he's literally Superman). Have we been paying attention closely enough to all the 'Jed herrings' he's left us?

He has also left a huge section of the population on the edge of their seats as they try to work out what on earth went on/is going on/might go on/whether or not this stuff actually is going on. But what questions do we need to see answers to on Sunday night? I'm glad you asked.

In a nutshell, we need to know if MI5 is behind the terror attacks, if the Prime Minister tried to kill Julia, who Longcross is, what is hidden on the 'Kompromat' (Russian for 'compromising material'), who Chanel and Luke Aitkens really are – oh the list is endless. Well, not endless. Let's have a look.

Eastern Daily Press: Richard Madden as David Budd in series finale of Bodyguard. (C) World Productions - Photographer: Sophie MutevelianRichard Madden as David Budd in series finale of Bodyguard. (C) World Productions - Photographer: Sophie Mutevelian (Image: WARNING: Use of this copyright image is subject to the terms of use of BBC Pictures' Digital Picture Service (BBC Pictures) a...)

The questions we need answered in the last episode of Bodyguard

1) When are the security services going to make the connection between David Budd and his former army comrade-cum-suicide-assassin Andy Apsted? Why haven't they made it yet? Don't they have access to Google?

Eastern Daily Press: Richard Madden in BBC series Bodyguard. Picture: BBC/WorldProductions/Sophie MutevelianRichard Madden in BBC series Bodyguard. Picture: BBC/WorldProductions/Sophie Mutevelian (Image: WARNING: Use of this copyright image is subject to the terms of use of BBC Pictures' Digital Picture Service (BBC Pictures) a...)

2) What's on that iPad that Julia led David to thanks to her throwaway comment about the Death Star?

3) Why don't the security service want David to find out who killed Julia? Surely it's in the public interest that the perpetrators are unmasked?

4) Is Nadia a reliable witness? She's changed her statement to say that the man who gave her husband the bomb vest was Shawcross rather than the West Asian man she reported first. Is she telling the truth?

5) Just who did swap the bullets in David's gun for blanks? And why?

Eastern Daily Press: David Budd (RICHARD MADDEN) and Julia Montague (KEELEY HAWES) - (C) World Productions - Photographer: Sophie MutevelianDavid Budd (RICHARD MADDEN) and Julia Montague (KEELEY HAWES) - (C) World Productions - Photographer: Sophie Mutevelian (Image: WARNING: Use of this copyright image is subject to the terms of use of BBC Pictures' Digital Picture Service (BBC Pictures) a...)

6) Is David's PTSD causing him to have memory blanks or to forget what he's actually done?

7) Did Tahir Mahmood know about the pressure sensor on the stage which triggered the bomb?

8) Who is Charlotte Foxfield, the woman named as the victim of a sexual assault in the files Julia was given? Her name is definitely memorable enough to mean that she's going to pop up at some point.

9) Has Lorraine Craddock (David's boss) got anything to do with Julia's murder? She called her a 'dangerous politician' – why?

10) Who is the acting Home Secretary, Mike Travis, taking orders from? Did he conspire to kill Julia?

11) Just what is Chanel Dyson doing? Why does she have a Range Rover with blacked-out windows at her personal disposal, the same one which was at the meeting for hacked-off soldiers organised by Andy Apstead? Is SHE Charlotte Foxfield? Why did she call herself Sam in the café?

12) Even if she isn't Foxfield, we all know the lore of crime dramas thanks to writer David Baldacci, who points out that if a minor character reappears later on, there's a good chance they will be the key to the answer. Is she?

13) Genuinely, why don't the BBC learn from American dramas and give the writers a little bit more breathing space with a whole lot more episodes to play with? Six episodes just isn't enough. Do you think HBO would have accepted six? No. Twelve would have been far better.

14) Surely Prime Minster John Vosler is unlikely to have arranged to have Julia bumped off, even if she was keen to, er, bump him off the top slot?

15) Has Roger Penhaligon (Julia's ex) got more to do with this? He was furious when he found out that Julia had been to Chequers…

16) Do spies get given some kind of DIY manual to help them find all the handy places you can stash things in around the house, like behind panels in boilers, etc?

17) I'm not sure I trust PC Tom Fenton. I don't know why. Is he our police mole?

18) Has Vicky's new boyfriend got anything to do with what's been happening? Is he using Vicky to get to David? Does Vicky know more than she's letting on?

19) One of the fan theories is that the man that Nadia initially said had given her husband the bomb vest, before she agreed with David that it was the shady 'Richard Longcross', is DCI Deepak Sharma – surely not?

20) Is DS Louise Rayburn as innocent as she seems? Didn't she seem to know where David had previously hidden his gun?

21) Gina McKee seems to have a suspiciously small role for such a brilliant actress (as did Keeley Hawes) – is Mecurio saving her for a grand final hurrah? Is SHE the police mole? Is she helping or hindering David?

22) Why WOULD Julia send David to 'the Death Star'? Did she know her life was in imminent danger? Did she know she might be, ahem, about to disappear off the scene?

23) Was Julia a goodie or a baddie? Is the Prime Minister John Vosler a murderer?

24) Why has Richard Longcross been spying on David's family?

25) Luke Aitkens is the driver of the Range Rover, but what is his involvement in what has happened?

26) Rob MacDonald has confessed that he was part of a plot to discredit Julia as she made a keynote speech but that he knew nothing of an assassination plot – is he telling the truth? (It doesn't help that Rob has the smuggest face of all time)

27) Does anyone else hear the words 'yes, Sire' after anything that the actor playing Stephen Hunter-Dunn (Stuart Bowman) says because they're so used to seeing him playing Bontemps, Louis XIV's loyal manservant, in Versailles?

28) On which note, did security chief Hunter-Dunn turn against Julia and order Longcross to supply a bomb to Nadia's husband?

29) Was Andy Apsted a lone wolf or was he part of a wider conspiracy?

30) Is 07700 900431 David Budd's real phone number? (I know the answer to this one: no – 07700 900000 to 900999 are kept free so that TV shows can use them without someone's phone being bombarded by calls. OR THAT'S WHAT 'THE MAN' IS TELLING US.

31) Did David do it? We did see him harbouring anger towards the Home Secretary, almost strangling her in his sleep and he was in charge of the security sweep before her death…

32) I mean it did look like he was leading Nadia to identify Longcross as the bomb supplier after convincing her that he was on her side, didn't it?

33) The 'Montague' surname and the doomed romance: this isn't a link to Shakespeare's Romeo and Juliet, is it? Does that mean our hero might not make it out alive either? A Budd by any other name…

34) Why is David buying a rifle? Why did the man he's buying it from not have an umbrella? Do gangland arms dealers not use umbrellas?

35) Is it all going to be a Murder on the Orient Express-style plot? Did EVERYONE kill Julia?

36) Is there any credence to the Reddit thread which suggests that Budd is '…the instrument of carnage in a Winter Soldier style reprogramming which has turned him into a zombie deathbot'?

37) Look: let's not beat around the bush any longer: is Julia alive, or not?