The term ‘county lines’ describes the practice of using children to traffic drugs from cities to coastal towns and rural areas, an under-reported fact of modern British life. Inspired by the stories he heard while mentoring kids at an East London pupil referral unit, writer-director Henry Blake‘s powerful feature debut boasts a compelling central performance by Conrad Khan as 14-year-old Tyler, whose mum Toni (Ashley Madekwe) is struggling to provide for him and his sister.