* English children are the most tested in the world. It is estimated they will undertake up to 105 tests and exams during their school years
* Scotland has never had key stage testing and league tables
* The Welsh have been edging away from the English system, recently abandoning key stage 1 testing and now looking to change key stage 2
* ChildLine receives 800 calls a year from pupils suffering exam stress, some of them as young as nine
* The annual cost of exams and tests has shot up to more than pound;200 million - a 50 per cent rise - since Labour came to power
