From the Times October 12th:

TEACHING unions formed a united front yesterday against introducing new methods of fast-tracking experienced teachers who wish to transfer from the private to the state sector.

England lacks 3,500 mathematics teachers in its secondary schools. But in spite of this chronic shortage, Steve Sinnott, general secretary of the National Union of Teachers, said the rules should not be changed.

Last year 2,005 teachers moved from maintained to private schools, while 640 teachers moved from private to state schools.