Prince George could be an Islamic State terror target after UK media reported a specific threat to the four-year-old son of Prince William and Kate Middleton.

The threat, stating “Even the royal family will not be left alone” appeared as part of a message posted by anonymous IS members on the Telegram messaging service, the Daily Star Sunday reported.

George, who is the third-in-line to the British throne, started primary school near the family’s Kensington Palace home in central London last month.

The threat reportedly included an image of George next to a photo of his school in Battersea, south London, accompanied by its address and the caption “school starts early”.

The Royal Family does not comment on security issues.

 The message also featured a section of an Arabic jihadi song which translates as: “When war comes with the melody of bullets, we descend on disbelief, desiring retaliation.”

IS is known to favour Telegram as a messaging system because its contents are encrypted and it keeps the user’s location hidden.

British intelligence officials are believed to be regularly monitoring Telegram for IS messages. 

Concerns over the security of George were previously raised last month when a 40-year-old woman was arrested allegedly attempting to break into the young royal’s school.

The woman was charged with suspicion of attempted burglary in relation to the incident and is suspected of having gained access to the school at about 2.15pm local time, while the Prince was in attendance.

London’s Metropolitan Police at the time said it would be reviewing security arrangements at the school following the arrest.

Days before the Prince was due to start school, a local resident filmed herself wandering its corridors unchallenged.

Doctor Sarah Burnett-Moore, 54, walked into  the school after the front gate and a main entrance door were left open.

She said the lack of security at the school was “astonishing”.

“I could have walked in with an IED and set it to go off,” she said.

Prince George, the great-grandson of Queen Elizabeth, is the oldest child of William and Kate. He and sister Charlotte are expecting another sibling in April.