Key Stage 2 test markers, who are practising or retired teachers, receive thorough training and undergo a number of quality checks through the marking process.

BBC: Head teachers complain of 'erratic' Sats marking

He added that what began with a throwaway comment took on a life of its own with the teachers practising secretly after school so the pupils did not find out.

BBC: Teachers reward pupils with Gangnam Style performance

There were four days of scrutiny at report stage and the government won all divisions, including one on a Labour amendment which would have ensured that all teachers practising in the classroom have qualified teacher status.

BBC: Education Bill clears the House of Lords