Amid predictions of widespread redundancy, she condemned education funding as “pitiful, shameful and criminal”, and threw the words of the Prime Minister back by demanding: “If education is a Government priority, where is the investment? How do you carry out whole-class teaching when there is not enough equipment for the whole class?” Mrs Gunn, president of the National Association of Schoolmasters Union of Women Teachers, asked delegates.

“How do you organise group activities for 35 pupils in a classroom where, however many electrifying science experiments you carry out, you simply cannot transform it into Dr Who’s Tardis? How do you find time to plan, prepare, mark, assess, climb up walls to create astonishing displays of children’s work, act as co-ordinator in several subject areas, and attend multifarious and multitudinous meetings when you have no non-contact time?” She attacked the Government on funding for all sectors and said: “There is a complete contradiction in the Government’s call for a marked improvement in post-16 provision and recruitment rates and Mrs Shephard’s ungracious rejection of any financial responsibility.”

She called for nationally-agreed class size limits for primary and secondary schools, and dismissed as weak Government claims that there was no evidence linking smaller class sizes and pupil achievement “when every study on why parents chose independent schools has class size near the top of the list”.

Mrs Gunn, from Hesleden primary in Cleveland, said education was at a crossroads, with schools now employing part-time and non-qualified staff because they could not meet the cost of full-timers.

She said that from 1989 to 1994, 12,700 full-time teaching posts had been lost, while at the same time 12,700 part-time teaching posts were created along with 39,400 non-teaching posts.