The NASUWT later estimated that around 15,000 people had taken part in a march organised in London.
Today's strike action has been a great success and is an indication of the anger and concern that teachers share about the changes this Government is making to the profession.
Strike action does of course always come at a price and we are very well aware of the disruption this causes to parents' working lives as well as their children's education.
Michael Gove has demoralised an entire profession and today's action is a direct result of his and the Government's steadfast refusal to accept there are problems that need to be resolved.
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The high of 35C was recorded on a Bakerloo line train between Piccadilly Circus and Oxford Circus at 2pm.
Weather forecasters say temperatures could reach 35C, beating the previous record of 34.6C in the scorching summer of 1976.
After years of political manoeuvring over the future expansion of Heathrow Airport, there has been an important development this lunchtime.