★★★

The leap from school textbook alternative to all-star, big screen bonanza is about as impressive as they come in the world of non-fiction. Dating back to the nineties, Terry Deary’s Horrible Histories books have spawned magazines, plays, proms, video games, theme parks and two BAFTA winning television series to gain renown as a British institution. It’s an empire even the Romans would be proud of – thus making said ancient civilisation an apt starting point for the franchise’s new cinematic lease of life. Whilst Rotten Romans does little to convince that narrative structure is the future of the franchise, its winning cast and good nature carrying things through. More laughs would have been welcome all the same.

Genes flow fluidly from CBBC’s hit series into the film, which comes directed by Dominic Brigstocke. New leads might relegate the small screen stars to cameos but retained are grotty puppet Rattus Rattus (voiced, as on TV, by John Eccleston) and a selection peppy song and dance routines. Kate Nash particularly excels in this regard, transforming Boudica, iconic rebel and Queen of the Iceni tribe, into a folk and roll headliner on tour. She ‘destroys’ St Albans and sets London on fire. Literally. Other numbers prove easier to forget but Nash shares her gung-ho energy for fancy dress fairly accords the board. When a film launches with Sir Derek Jacobi being offed – from a role he last played in 1976 – by a bitchy Kim Cattrall, that’s always a good start.

It’s not the biggest names, however, that rule this roost. Sebastian Croft and Emilia Jones play Atti and Orla. He’s the brainy-not-brawny Roman soldier sent to Britain for upsetting the Emperor – ‘a fate worse than death’. She’s the wannabe Celt warrior, desperate to switch her father’s (Nick Frost – who plays dads now) safety net for a place at Boudica’s side. If it seems that they’re destined for a bosom friendship, first they must overcome the differences that entitle them foes. When Atti pauses mid-route march to tie his sandals, Orla knocks him on the head with the hilt of her sword and declares him her prisoner. For the remainder, hijinks fall in their path, albeit with somewhat passive diversionary impetus. This is, at times, a peculiarly uneventful slice of historical storytelling and one that only occasionally lives up to the name horrible – toilet humour notwithstanding.

Ultimately, it is the shadow of the television series that haunts Rotten Romans. Were its sketch show format not so fiercely, relentlessly even, entertaining, perhaps the film would not seem quite so lacking in lustre. Jessica Swale, Giles Pilbrow and Caroline Norris’ try hard gag rate throws up enough chuckles along the way to endear but most drift by. What’s curious here is that the film’s strongest flairs are those which mine comedy from bonafide factual truth. Much like in the television show. There’s the terrific recurring joke-not-joking about dog licks being considered curative in Celtic Britain and a joyful subplot devoted to the infantile Emperor Nero’s (Craig Roberts – great) repeated attempts on the life of his mother (Cattrall’s Agrippina). Stick around for the credits to hear more from Rattus Rattus about what was and wasn’t true. Alas, the Battle of Watling Street did not really incorporate a dance off.

Considerably quainter than its anarchistic forebears, Rotten Romans is never less than perfectly watchable. If this is to be the first of many extended and rather nicely budgeted episodes in history then a zanier second outing would be welcome. Something sharper, sillier, smarter and distinctly more horrible please. If this can be achieved, and a new legacy formed, then by all means carry on coming.

T.S.