This British film about an autistic teenage maths whiz (Asa Butterfield) could have been formulaic, but the deft acting, inventive script and striking photography make it special.

Butterfield is convincingly naive and socially awkward as the gifted, emotionally withdrawn young savant and he gets warm, sympathetic support from Sally Hawkins as his widowed single mum and Rafe Spall as his teasingly glum, MS-stricken teacher, a former maths prodigy who failed to fulfil his potential.

Inspired by director Morgan Matthews’ own 2007 BBC documentary, Beautiful Young Minds, the story sends its hero to a maths training camp in Taiwan, where his unexpected friendship with a Chinese competitor finds him grappling with feelings that can’t be reduced to an equation.