Performance-related pay will not be applied to teachers' salaries until a year later than expected, TES has learned.
The controversial overhaul of teachers' pay, which will bring about the end of automatic rises and the effective abolition of the main pay scale, will not affect pay packets until September 2014, instead of this September as had been anticipated.
Official guidance on how to implement the changes is not expected to be published until the summer, leaving insufficient time for schools to change their pay policies for the 2013-14 school year.
The news comes as the pay reforms - proposed by the School Teachers' Review Body and approved by education secretary Michael Gove - came in for strong criticism at the annual conference of the Association of Teachers and Lecturers (ATL) in Liverpool this week. Members unanimously backed a motion that the union "opposes and deplores the destruction of teachers' national pay structure".
Mark Baker, a teacher at Redwood Secondary School in Rochdale, Greater Manchester, told the conference that the pay changes would leave teachers with "stagnant career prospects" and a "low-pay culture without progression", which could cause an increase in "teaching to the test and cheating".
Martin Freedman, ATL's head of pay, conditions and pensions, said schools would still have to honour incremental pay rises due under the current system this September. "Although the Department for Education said legally (the new system) will be introduced in September, there will be no appraisal system in place to justify performance-related pay," he said.
"Schools won't be getting the details until June or July, so it will be too late for them to implement for this year. There are 500,000 contracts that will have to be altered."
Russell Hobby, general secretary of heads' union the NAHT, said he was advising members that teachers' salaries would not be affected by the pay changes until next year. "This will take time to happen. Schools need to get a new pay policy in place to enable decisions to be made," he said.
On Wednesday, shadow education secretary Stephen Twigg told the ATL conference that a Labour government would protect national pay structures. "National pay machinery is crucial. This gives teachers the protection that they deserve and maximises efficiency of administration," he said.
Performance-related pay is also expected to face strong criticism at the NUT and NASUWT annual conferences, which take place over the Easter weekend. The unions last week announced a programme of regional and national strikes over pay, as well as pensions and workload.
"There have been no changes to our plans," a DfE spokesperson said. "The new pay arrangements will come into force from September 2013 - as planned - so schools can set out how the year's appraisals will be linked to pay and teachers can receive their first performance-related pay increases in September 2014."