King Charles and his wife Camilla were not in the estate at the time of the incident but Prince William and his family were believed to be at Adelaide Cottage, part of the Windsor Castle estate, the Sun reported.

Burglars broke into the grounds of Britain's royal Windsor Castle in October and stole two vehicles from a barn, Thames Valley Police said.

Police are investigating the incident on the Windsor Castle estate, which is where the Prince and Princess of Wales and their children reside in Adelaide Cottage

The offenders entered a farm building and and “made off with a black Izuzu pickup and a red quad bike,” Thames Valley Police told NBC News in a statement Monday.

The royal estate where William, Prince of Wales lives with his wife Catherine, Princess of Wales and their children has been targeted by masked thieves who smashed through a gate close to their home to steal farm vehicles from a barn.

Two men reportedly climbed a six foot fence during the night to steal farm vehicles. The crooks are said to have then driven off in a pick-up truck and on a quad bike that had been stored in a barn.

Masked thieves have caused a major security fright at the Windsor Castle estate, as they broke in while Prince William, Kate Middleton, and their children were asleep at their nearby residence. The intruders reportedly scaled a six-foot fence under cover of darkness to pilfer farm vehicles.