Angry parents whose daughters are afraid to use mixed-sex school toilets have threatened ministers with legal action unless girls’ and boys’ facilities return.

Thousands of single-sex blocks have been replaced with mixed-sex toilets as schools seek to accommodate pupils who say they are ‘non-binary’ or trans.

The move has provoked widespread complaints that mixed lavatories discriminate against girls and can lead to taunts, bullying and ‘upskirting’.

Now parents have written to Education Secretary Lucy Powell warning they are prepared to go to court.

The families have commissioned damning new legal opinion which concludes that schools failing to protect the ‘privacy, dignity and safety’ of their pupils are open to legal action.

One father of a 14-year-old girl said she had started skipping school to avoid mixed-sex toilets.

Read more: Furious parents whose daughters are afraid to use mixed-sex toilets at school have demanded that ministers rebuild separate facilities or face court action