Liar: will Andrew face justice? 10 questions for tonight's finale

The moment of truth is at hand for ITV psychological thriller Liar. Will dashing medical professional / monstrous sexual predator Andrew Earlham (Ioan Gruffudd) finally face justice for his crimes?

Or, having made a life-long career out of avoiding detection, could the slippery surgeon once more evade the law? 

With just one episode to go things are very much up in the air in Harry and Jack Williams unnerving drama, with victim Laura Nielson’s bid to frame her attacker in the process of falling apart and the preening villain confident the police won’t be able to prove he assaulted DI Vanessa Harmon.

But if the previous five weeks have taught us anything it is that nothing is predictable in Liar – so buckle up for a twist or 10 as we hurtle towards the finish line. Here are the key questions to ponder ahead of tonight’s much anticipated finale:

1. Is Andrew acting alone?

Doctor Depraved didn’t flinch when Harmon (Shelley Conn) predicted police would uncover DNA evidence proving he had raped her at her house. "No you won’t, detective… no you won’t," he hissed and slouched into the night, walking off the effects of the GHB drug with which Laura had spiked his drink. This has raised the suspicion that Andrew might not be working alone and that his misdeeds may be even ghastlier than previously imagined. Is he merely an enabler for another sex predator? If so, will the real villain be unmasked? 

2. What is Andrew keeping in the shed? 

The lengths Andrew went to in order to stash a suitcase at the end of his mother’s garden suggests it holds more than his collection of Mojo back issues. The memory cards he also hid in the outhouse appear to contain video footage of his attacks. But clearly it’s the case that contains the most important material. We’re dying to discover more.

3. What does his mother have to do with all this? 

On his courtesy call to mum, Andrew was affable and loving. But the look on his face when Laura (Joanne Froggatt) mentioned his mother hinted at unresolved conflict. “You’re scared of me. You’re scared of all women," she said. "What happened to you? Was it your mother? It usually is.” Will a dark truth about Andrew’s upbringing be produced from a hat as the explanation for his abhorrent behaviour? 

4. Is Laura planning to kill Andrew? 

Bumping off the man who destroyed her life surely crossed Laura’s mind when she bundled him off to the boat-shed. How else to explain the murderous glimmer in her eye when she menaced him with that knife? Now that her plan of framing him for a second sex attack has come unstuck, might she resort to a simpler, bloodier strategy?

5. Is DI Harmon being set up for a tragic conclusion? 

Viewers' hearts will have jumped to their mouths as the pregnant detective underwent a baby scan last week. She has already endured drugging and sexual assault at the hands of Andrew / Andrew’s mystery conspirators (we have our pet theory and we’re sticking to it). Will her unborn baby pay the ultimate price for the physical and emotional grinder she is being put through? 

6. For how long have Katy and Tom been carrying on? 

Was Laura’s married sister (Zoe Tapper) copping off with suspended cop Tom (Warren Brown) when he was still with Laura? Have we, moreover, seen the last of Liam (Richie Campbell), Katy’s upstanding husband who has walked, heartbroken, out of her life? And do the viewers who early on identified him as a potential sex attacker still feel guilty for their grievous misdiagnosis? Of course they do. 

7. What was Andrew watching on the pocket camera? 

One might assume that he has been filming his assaults and was enjoying a quick jog down memory lane before his mother’s carer rudely interrupted him. All will presumably be revealed.

8. Could Laura be in trouble? 

She drugged Andrew, then bundled him off to a shipping yard. If the police are minded to investigate, the crime scene is littered with damning evidence. A drama that enjoys its horrible ironies wouldn’t be above delivering a final sickening twist and putting Laura in the firing line. 

9. What part will the minor characters play? 

Harmon’s wife Jennifer (Jill Halfpenny) is a soldier serving in Iraq, to whom we were briefly introduced via a video call in part four. Is it possible she will re-surface in the finale (according to the Internet Movie Database, she is to feature in two episodes). And what about Catherine McAulay (Dawn Steele), best friend of Andrew’s late wife – and another of his victims? There is every chance these, and other, secondary characters have a part to play – assuming the closing instalment does not boil down to a game of cat and mouse between Laura and her assailant.  

10. Are we being prepared for a sequel?

Episode one of Liar trounced BBC rival Rellik in the ratings (awkwardly, both are from the bloody pen of the Williams brothers) while subsequent instalments have achieved solid viewing figures. Given its ongoing success, is ITV setting us up for a sequel? With so many forces now arrayed against him, you wonder if Andrew can plausibly be shown living to sneer another day. 

Liar episode six airs on ITV at 9pm tonight