Ed Balls discounts the argument that International GCSE is a superior exam ("IGCSEs sideline Shakespeare and mental arithmetic", March 20). The exam boards agree with him. On its website, Edexcel promotes an alternative international exam as being "probably the most recognised school-leaving qualification in the world". Cambridge's international board promotes this exam with equal enthusiasm for being "a mark of quality and evidence of real ability". And what is this gold standard qualification? It is the exam whose name we dare not mention. It is the exam we, effectively, banned in this country 20 years ago. It is the GCE 'O' Level.
Chris McGovern, Heathfield, East Sussex.