Inspectors have been prepared to cope in schools where all pupils take part in the literacy hour at the same time.

However, Chris Woodhead, the chief inspector of schools, has reassured the heads’ unions that the Office for Standards in Education does not intend to police the literacy strategy. Ministers are keen that primary schools should adopt the centrally-designed approach to literacy and the onus is on heads to opt out, rather than opt in.

The letter to David Hart, general secretary of the National Association of Head Teachers, makes clear that judgments about literacy standards will continue to be made against existing criteria and inspectors will not comment on whether teachers are implementing the strategy. It says OFSTED will judge each school’s achievement on its merits.

The guidance that has gone out to local authorities says schools must attend a two-day conference on the strategy and reserve three days for training. Schools which decide not to take part will be expected to show that they have a literacy scheme that is as comprehensive as the Government’s.

The NAHT says that inspection reports should not refer specifically to the fact that a school has decided not to sign up to the scheme.

“We shall challenge any statement that is made about the non-adoption of the literacy strategy,” says Mr Hart.

Inspectors will begin to report on the literacy strategy in the pilot schools in September and all primaries in mid-autumn.