Christine Blower, the general secretary of the National Union of Teachers, says Education Secretary Michael Gove is "isolated" in his view that GCSEs should be replaced.
She said: "Michael Gove and the Coalition Government's position on examination reform is now surely untenable. The Education Secretary is totally isolated in his view that the English Baccalaureate Certificates are a suitable measure to replace GCSEs."
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British soldiers will join troops from some 30 countries who work in the country.
The demand comes after the Prime Minister urged a "grown up" relationship between her government and the devolved administrations.
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