In 2009 more than one in five children left primary school having failed to grasp the basic maths skills required by the national curriculum. In a two-part special, Dispatches asks why and how are we failing Britain's children when it comes to maths. Dispatches follows a class of final-year pupils at Barton Hill Primary School in Bristol as their staff adopt a radical approach to teaching, in a bid to improve the maths ability of these children before they head off to secondary school. The problem couldn't be more urgent. Research shows that failing to grasp the fundamentals of maths at primary school leaves only a one in ten chance of catching up by the age of 16. Dispatches hears from leading lights in the worlds of business and academia - including the CEO of Sainsbury's, Justin King, and George Davies, formerly of Next and Asda - about the impact on the economy and on adult life of leaving school without basic maths skills. In a provocative nationwide exercise, Dispatches examines the standard of primary maths teaching in this country by testing the teachers. No tricks; just 27 questions that a bright 11-year-old would be able to answer. The shocking results are revealed in the programme.