After last week’s deliciously dark closing sequence hinted at Gemma (Suranne Jones) seizing the upper hand in the battle with Simon (Bertie Carvel), episode two was something of a surprise.

Simon’s return to Parminster is far more cunning that we first realised and his plot to chase Gemma out of town has been planned for a while.

He has started taking revenge on those who wronged him in series one and used an old friendship with Gemma’s colleague Sian (Sian Brooke) to get updates on his ex-wife’s activities.

[Read more: Doctor Foster series 2 episode 1 review - 8 burning questions]

It looks more and more like his return to town is purely about revenge on Gemma rather than any business venture.

Here are our five burning questions after episode two.

1. Who is to blame for Tom’s anxiety and violence?

Gemma’s drunken grilling of Tom’s poor pal Max was a new low for the doctor. Even though we have zero sympathy for Simon, this week was a dark passage for Gemma and her blindness to what’s going on around her has clearly impacted on her son.

Simon’s behaviour in series one will have cast a cloud over Tom, but does his mum have to face up to her own problems? She barely spent a minute without a glass or bottle (or two) this week.

Bertie Carvel in Doctor Foster series 2. Photo credit: BBC

Regardless of Gemma’s bad behaviour, something is obviously lurking in the background with Tom and Simon. His sudden turn against his mum can’t have come totally out of the blue. What can the smirking sleaze have told the teenager that would make him hate his mum?

2. Is this the filthiest TV drama BBC One has ever aired?

It might not be wall-to-wall sex scenes, but Doctor Foster is brimming with sexual tension and this week’s episode was stuffed with smut and innuendo.

We suspect there was a rush of google searches for “butter churning” (we advise not going there) and Gemma’s drunken dance routines and brazen antics will probably get certain sections of the media hot and bothered.

[Read more: Doctor Foster series 2 - meet the cast and characters]

It’s a credit to the casting team that every time a duo are left alone together, even in the most innocuous situations, the show sizzles.

3. Does Gemma have any true feelings for James (Prasanna Puwanarajah)?

Suranne Jones in Doctor Foster series 2. Photo credit: BBC

“That was the best I ever had.” “Yes, it was good.”

Poor old school teacher James. Dragged along to Simon’s party last week, called out for a drunken booty call at Parminster’s surprisingly popular nightclub this week. He’s definitely fallen head over heels for Gemma and is forgiving of even her most shocking revelations, including the fact that she paid a man for sex earlier this year because she can’t handle relationships.

Does she actually feel anything for James or is he just a handy friend to have around? We suspect it’s the latter and she’s too wrapped up in Simon to notice what a great guy she has on her hands.

4. Is Kate (Jodie Comer) having an affair?

Still from Doctor Foster series 2, episode 2.  Photo credit: BBC

Simon said that he knew about the man Kate was spending an evening with at the house and their kiss on the doorstep wasn’t passionate, so maybe he’s correct.

[Read more: Where is Doctor Foster filmed? Where is Parminster?]

However, it would be sweet justice if it turned out that Simon was ditched by his wife for a younger model after everything that he’s done to Gemma and all the barbs about her age and letting herself go.

Perhaps his obsession with Gemma and revenge has meant he’s let things slip at home.

5. And… what was in Gemma’s present for Kate?

It wasn’t mentioned this week, but it looks likely to be a key plot twist in the series. Does anyone have any suggestions for what might have been in the box that she gave her at the party? Let us know in the Comments below.

[Read more: Doctor Foster - what happened in series 1?]