London: UK police said on Monday officers were investigating a break-in last month on the grounds of the royal Windsor Estate, reportedly while Prince William and his family were at home.
Thames Valley Police said the intruders stole two vehicles from a farm building on the estate west of London on October 13 and that no arrests had been made.
"At around 11:45 pm on Sunday 13 October, we received a report of burglary at a property on Crown Estate land near to the A308 in Windsor," the force said in a statement, referring to the castle grounds.
"Offenders entered a farm building and made off with a black Isuzu pickup and a red quad bike.
"They then made off towards the Old Windsor/Datchet area. No arrests have been made at this stage and an investigation is ongoing."
The Sun tabloid, which first reported the incident, said the "masked raiders" struck while William, his wife Catherine, Princess of Wales, and their children slept in their nearby home on the estate.
The newspaper reported last month that armed police officers from the Metropolitan Police's diplomatic protection unit had been removed from the two main gates of the Windsor Estate.
It comes as the force faces a shortage of firearms officers, with far fewer candidates joining up, the tabloid said.
The Metropolitan Police, which is responsible for royal security, said it does "not comment on any security arrangements for protected individuals or sites".
But in a statement, a spokesperson said the arrangements were "kept under constant review to ensure we take into account the latest threat and risk information and assessments that are available to us".
The burglary is the latest security breach at Windsor, where William and his family live year-round and was the favoured residence of the late Queen Elizabeth II.