But the Government has a long way to go in convincing all teachers that the hour really works - with more than a third in this survey saying it is not a good approach to teaching literacy and a quarter still undecided.
While 97 per cent of schools are using the literacy hour, ministers may be concerned that more than half the respondents have modified it to suit their own pupils. A further third would like to do this.
OFSTED officials have raised concerns that phonics is not being taught in half of the literacy hours inspected last term.
Teachers are more worried about insufficient training, lack of teaching materials, and workload. Ninety per cent of the 500 respondents said the literacy hour had created "a lot" of extra work.
Doug McAvoy, NUT general secretary, said: "There is a lack of conviction about the value of the hour as well as widespread concern about under-resourcing and workload. Imposition has not motivated teachers but in many cases has contributed to that lack of conviction.
"Successful change depends on harnessing teachers' commitment and enthusiasm. Their professional judgment and experience must be respected." The Government should offer further training opportunities and ensure extra funding for teaching materials, particularly big books, he added.
The NUT findings are not necessarily representative of all teachers. They are based on the first 500 responses to the survey, distributed in the union's magazine last month. Teachers' comments reveal mixed feelings about the hour, and strong objections to the level of prescription - even though the strategy is not compulsory.
"There are some elements of the literacy hour which I am happy to take on board and much that is not at all new.
"What saddens me is that if all the money spent on it had been spent on training and recruiting full-time support for all primary classes, the aim would have been delivered," said one teacher.