As Prince William's family slept in their home at Windsor, masked intruders broke into the estate.

Masked intruders weaseled their way into the Windsor Castle estate to commit an alleged robbery, as the Prince and Princess of Wales and their children slept in a nearby cottage. 

The Sun reports two masked men broke into the estate in October, stealing two vehicles from a barn located on the property. 

It's understood King Charles and his wife Camilla were not at the estate, but the Waleses — including children Prince George, 11, Princess Charlotte, 9, and Prince Louis, 6 — were asleep at Adelaide Cottage, which is also located on the estate. 

The two men used a stolen truck to break through a security gate in the middle of the night, then scaled a two-metre fence, per The Sun. 

It's believed they made off with a pick up truck and a quad bike. Thus far, no arrests have been made.

Two men broke into the grounds of Windsor Castle. Image: Getty

A source told the publication, "They must have been watching Windsor Castle for a while."

At this stage, there is no suggestion that the Waleses were in direct danger from the intruders. 

The Windsor estate measures 16,000-acres and Prince William has his own security detail at Adelaide Cottage. 

However, the break-in was relatively close to their residence. The intruders entered through Shaw Farm Gate, which is less than 1.6 kilometres away from Adelaide Cottage.

Neither Buckingham Palace nor Kensington Palace have released statements on the matter. 

It's unusual for them to comment on royal security, and also rare to get a comment from the Metropolitan police on such matters. 

Windsor Castle sits on a large estate, but it's believed the burglary happened under 2km away from the Waleses' cottage. Image: Getty

However, Town & Country report that Thames Valley Police gave a statement. 

"At around 11:45pm on Sunday, October 13, we received a report of burglary at a property on Crown Estate land near to the A308 in Windsor," it read.

"Offenders entered a farm building and made off with a black Isuzu pick-up 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."

This is the second time the walls of Windsor Castle have been breached in the last five years. 

In 2021, a man was arrested on Christmas Day when he entered the grounds with a crossbow, saying he was there to kill then Queen Elizabeth II. 

He was later sentenced to nine years jail. 

-With AAP

Feature image: Getty