NQTs looking for tips would do well not to follow the example set by Zoe, the lead character in the first of the Bush Theatre’s two new plays about schools.

The Knowledge plunges the audience straight into the twenty-something’s embarrassingly naive attempts to teach citizenship to pupils in a failing Essex comp who regard themselves as “retards”.

Zoe, convincingly played by Downton Abbey star Joanne Froggatt, falls into every trap set for her by mouthy teenagers and fellow staff alike.

When not initiating classroom discussions about anal sex, she is busy asking pupils how she should teach and unwittingly encouraging a teenage crush.

John Donnelly based his new play on a decade working in real schools - and it shows. The four teenagers - great performances from Kerron Darby, Holli Dempsey, Joe Cole and Mandeep Dhillon - initially sound a bit too much like Catherine Tate caricatures, but it doesn’t last.

That minor point aside, The Knowledge’s brilliantly staged, unsparing account of life in a tough school rings true. Andrew Woodall is superb as a hardbitten old classroom lag - “Insecure? That’s Guardian reader for wanker, isn’t it?” - who retains his humanity.

The fellow education hack who accompanied me to the Bush Theatre complained that there wasn’t much education policy. Thankfully, he was right. There is context - “Lose kids, lose money,” says science teacher Maz, explaining why disruptive pupils are not excluded.

But this is a play about people and the immense pressures that today’s “challenging” schools place on them. It reveals how thin the line between young teachers and their teenage charges really is and what happens when it is crossed.

Donnelly risks exploring some already well-trodden themes but more than pulls it off by with this fresh, thought-provoking drama.

And Zoe? She eventually masters teaching, but the consequences her mistakes have for her pupils hint at something darker than mere incompetence.