Some heads are demanding portfolios, observing teachers in class and even interviewing members of staff about their applications as they attempt to assess almost 200,000 forms by the end of term, according to the National Association of Schoolmasters Union of Women Teachers.
Meanwhile, teachers who missed the June 5 deadline for applications, because they were misinformed or for personal reasons, can still aply. They now have until July 14.
Nigel de Gruchy, NASUWT general secretary, said some heads appeared to have adopted observations and interviews as a blanket policy. He advised members not to co-operate. Teachers are also advised not to collect huge portfolios of evidence to support their claims - and to resist requests from heads who ask them to amend their forms.
"There is absolutely no need to collect portfolios or gather evidence together in preparation for the assessor's visit. It is a waste of time," Mr de Gruchy said.