Squatters have taken over a London house thought to belong to Saif al-Islam Gaddafi, police have confirmed.
A group calling itself "Topple The Tyrants" occupied the £10.9m house in Hampstead Garden Suburb in north London on Wednesday morning.
It said it would remain in place until confident the property's assets would be returned to the Libyan people.
The UK government froze assets owned by Libyan leader Col Muammar Gaddafi and his family last week.
The group's spokesman, Montgomery Jones told the BBC: "Saif Gaddafi and the Gaddafi regime have taken millions of pounds, billions of pounds in fact away from the people of Libya and used residences like this.
"We've taken it so that it will be returned to its rightful owners who are the Libyan people."
He added: "The police came to look around, then went away. The house isn't occupied at the moment but there are things to sit on."
The group said the property was managed by the Gaddafi family through a holding company registered in the British Virgin Islands.
The squatters unfurled a banner on the roof which read, "Out of Libya Out of London" and "Solidarity".
The group would not say how it got into the property or how many people were inside.
In a statement it added: "We didn't trust the British government to properly seize the Gaddafi regime's corrupt assets, so we took matters into our own hands.
"In the meantime we want to welcome refugees from the conflict in Libya and those fleeing tyranny and oppression across the world.
"We stand in solidarity with the Libyan people."
The eight-bedroom, Georgian-style house with swimming-pool and sauna had recently been put on the market for more than £10.9m. It was withdrawn from sale last month.
Describing the house, Mr Jones said: "It looks relatively nondescript from the outside but when you get inside you realise it is full of huge rooms and all the trappings of his status.
"It's palatial, it's got five storeys, it is full of marble and glass and other expensive materials. It's got a flat-screen TV in almost every room."
A spokeswoman for the Metropolitan Police said it was called to reports of unknown people entering an address in Hampstead Garden Suburb at approximately 1250 GMT.
"At this time this is being treated as a civil matter. There have been no arrests. Police are monitoring the situation," she said.
The UK Treasury has not confirmed the value of the Gaddafi family assets that it has frozen, but reports suggest a figure of £1bn.