Though Stefani owns the mansion, it's currently being rented out to Dame Elizabeth Forgan, head of the UK Arts Council, who was not home at the time.
It's being reported that some of Forgan's jewelery is missing and the front door is badly damaged.
Neighbors didn't notice that anything was amiss until 12 hours after the raid and the police were called in to assess the situation.
Gwen and her husband, Gavin Rossdale, live on the top floors of the mansion block with kiddies Kingston and Zuma. Apparently the burglars attempted to reach the family's part of the mansion, but were unsuccessful.
[Image via WENN.]