The government has delayed publishing its long-awaited transgender guidance for schools after its own legal advisors concluded some of the suggested elements would be unlawful, Sky News understands.

Prime Minister Rishi Sunak had promised to bring out the advice during the summer term, which comes to an end this week for most state schools.

But it is understood that three of the suggestions – including banning pupils from socially transitioning at school – would have been in breach of the Equalities Act.

Politics live: Sunak swerves question on rumoured reshuffle

Social transitioning means a child living in the role of their chosen gender, changing their name, pronouns or appearance as a result.

The other proposals in question are around schools requiring a doctor’s approval before a pupil can socially transition – known as a “medical gateway” – and advising teachers not to use a child’s chosen pronouns if they do not wish to do so.

Allies of the Attorney General, Victoria Prentis KC, said the government’s three law officers had advised that because some of the suggested guidance came up against the Equality Act, the government would only be able to go further on this issue if they introduced new legislation.

“This is a call for the prime minister now,” they said. “The Attorney General is in favour of the government being stronger on this.”

Speaking to reporters this afternoon, Mr Sunak said: “This is a really complex and sensitive issue because it affects the wellbeing of our children, and it’s important that we get it right given those complexities and sensitivities.

“I am committed to bringing forward that guidance, but I want to make sure that we’ve taken the time to go through it properly and when we do bring it forward, it will be well thought through.”

The PM promised back in March that the government would publish transgender guidance for schools in the summer term “so they know how to respond when children are asking about their gender”.

It is understood the strength of the guidance has been the subject of longstanding debate between different cabinet ministers.

A spokesperson for the Attorney General’s Office said: “By longstanding convention, reflected in the ministerial code, whether the law officers have been asked to provide legal advice and the content of any advice is not disclosed outside government without their explicit consent. That consent is rarely given.”

The prime minister’s spokesperson earlier said “this is a sensitive area, we do think more evidence is required before publishing”, but insisted more details will be set out as soon as possible.