The Teacher's Sheridan Smith digs into conspiracy in finale teaser

RadioTimes.com can exclusively reveal a first-look clip from tomorrow's finale that sees Jenna question Gabriel (Harry Hepple), the deputy head of the school both she and Cleary taught at.

The clip sees Jenna approach Gabriel at the gym to ask if he can remember Cleary, to which he replies that he can, before adding a major revelation: Cleary had previously slept with a pupil and ran off to Scotland with her.

"Cleary went to prison for it," he said. "God, I remember – we came back after the summer holiday and Cleary had gone. No explanation but obviously we all knew and talked about nothing else."

Jenna appears to be in disbelief at this news and says she had no idea it had happened, before Gabriel questions her as to why she's asking about Cleary.

"Why are you looking for him?" he says. "Reaching out to teachers who've been through the same sort of thing?"

"No, I'm not like him," she answers. "Look, nothing happened, the boy lied – but it was enough to set this all off, and now... I had no reason to ruin my life."

Jenna then presses Gabriel for more information about Cleary, but instead, he simply tells her: "You know I teach a lot of girls, some of them are very mature – but I never cross that line.

"I'm not their friend," he adds. They might think I'm unlikeable, strict. But the boundary is clear. Teacher, pupil."

Jenna soon counters: "Yeah, well I like to connect with my pupils, invest in them. I like them to feel good about themselves, that's..."

But Gabriel cuts in and says: "A good teacher – a responsible adult – keeps a respectful distance. Doesn't need to be liked."

He then begins to bench press, while Jenna stares into the distance. You can watch the clip in full below.

The Teacher concludes on Channel 5 on Thursday 3rd February. Looking for something else to watch? Check out our TV Guide or visit our dedicated Drama hub for the latest news.