A woman has been arrested after allegedly attempting to break into Prince George’s London school, prompting security fears for the four-year-old royal.

The son of Prince William and Kate Middleton started at Thomas’s Battersea private school last week in southwest London.

A 40-year-old woman was arrested on Wednesday and charged with suspicion of attempted burglary in relation to an incident at the school on Tuesday, London’s Metropolitan Police said.

The woman is suspected of having gained access to the school about 2.15pm on Tuesday, while the Prince was in attendance.

Police gave no details about exactly what happened. The woman remains in police custody.

“We are working with the school, which is attended by His Royal Highness Prince George, to review its security arrangements after the incident,” police said in a statement.

Thomas’s Battersea school, which Prince George attends. Photo: Getty

“Police are part of the protective security arrangements for the Prince and we will continue to work closely with the school, which is responsible for building security on its site.”

A spokeswoman for Kensington Palace, the residence of Prince William and his family, said: “We are aware of this issue but won’t comment on security matters.”

Prince George, the great-grandson of Queen Elizabeth, has another sibling on the way.

Earlier this month, Kensington Palace announced the Duke and Duchess of Cambridge were expecting their third child after George and two-year-old Princess Charlotte.

Prince William (L) arrives with Prince George on his first day of school. Photo: Getty