British music and lyrics duo Pippa Cleary and Jake Brunger, the writers behind the runaway fringe hit Jet Set Go (2008), have brought their musical adaptation of Sue Townsend’s iconic 1981 novel to the West End, following successes at the Leicester Curve (2015) and the Menier Chocolate Factory (2017).

There is not an atom of teenage grit in this squeaky-clean, primary-school style adaptation. The strong, optimistic melodies of Cleary’s sunny, jolly score have more in common with Sesame Street than with angsty eighties teen music, while a giant pencil-case set (Tom Rogers) and technicolour lighting (Howard Hudson) feels a lot more Bash Street Kids than Byker Grove. No teen has any spots (despite the constant reference to them) and no teen’s voice is breaking. The kids even do a nativity play at the end.

Given this choice to bleach out any hormonal nastiness, the cast are fantastic. There are four rotating child casts, and Wednesday night’s audience had the pleasure of seeing Rufus Kampa’s wide-eyed, charismatic interpretation of the title role. Pandora, the ambitious, private school-educated apple of Adrian’s eye, is played by Rebecca Mardin as a pitch-perfect blend of insufferable and sympathetic.

Being a diary, the show inevitably suffers a little bit from being too episodic, and not clearly enough about “a ______ who wants to ______”, so it feels a little structureless at times. While the adults in the cast nobly play a host of other characters (including Adrian’s classmates), a cast of ten is too small and stripped down for the West End. Come for light and laughter, but if you want angst and drama, stick to the book.

Booking online until 12 October 2019.