This article was corrected at 10.28am on September 21st.

A 12-year-old pupil is set to become one of the youngest people to transition in the world after her parents decided to allow her to return to school as a girl.

She was born male but if her parents and doctors agree then the 12-year-old may be the youngest person in the UK to undergo gender reassignment.

German Kim Petras – born Tim – became youngest person in the world to transition at 16 earlier this year.

The pupil, who has not returned to school since the story broke, was well-known among pupils and staff for her desire to live as a girl.

According to the Sun, pupils were ushered into an ‘emergency assembly’ and informed: “You may notice one pupil is not present in this assembly – that is because the pupil is now a girl.”

The pupil’s parents, who are under police protection from fear of attack, had hoped that the transition would be easier as the 12-year-old child was moving from primary to secondary school.

However, the school has come under fire from parents who are angry that they were not given warning.

“What has really upset the parents,” a source told the Sun, “is that the school didn’t see fit to send us a letter first so we could explain it to our children in our own way.

“Parents surely have a right to know when their children are being confronted with such sensitive issues as gender realignment at such a young age.”

In the UK, there is estimated to be around 15,000 trans people who self-identify as the opposite gender from the physical body they were born with.

Mermaids, a support group for trans children and teenagers, told PinkNews.co.uk:

“Sometimes schools are well prepared and it can work successfully, and sometimes the schools do not deal with it well, as in this current case,

“There is medical help available. What’s needed is more understanding within the general public, and earlier medical intervention.

“In the UK blockers to prevent further puberty can only be given once puberty is virtually over (at 16 years), but the Dutch protocol means that blockers could be started as young as 12 or 13.

“This protocol is being followed elsewhere, such as America and Germany.”