The government will break its own deadline to provide schools in England with guidance on policies for transgender pupils.
Prime Minister Rishi Sunak had promised the advice before the summer holidays, which begin this week for many schools.
The delay is because the attorney general for England and Wales has advised part of the guidance may be unlawful.
School leaders said the delay was frustrating.
One of the most controversial matters the guidance was expected to address is what schools should do if a child wanted to change their name, use different pronouns or change their appearance, hairstyle or clothes - what is known as socially transitioning - and whether to involve parents in the decision.
In 2020, a report commissioned by NHS England found that socially transitioning was not a neutral act - but neither was doing nothing - and more information was needed about its outcomes.
Ministers were considering advising against allowing social transitioning in schools altogether.
But, as first reported in the Times, the attorney general, Victoria Prentis, has said an outright ban would be unlawful.
A ministerial statement to confirm the hold-up is expected on Thursday.
