Armed robberies used a car in a "broken up" attack on a luxury store in Oxford, police said.
Police officers were summoned to Selfridges in central London on Tuesday after Thursday's fourth after the four suspects had driven Mini into the store to get in.
Two security guards tried to arrest the intruders, but one threatened the knife, and the other drove them.
The thieves stole the designer handbags and then escaped the other car, described as white VW Golf.
Selfridges announced on Tuesday the Press Association: "We can confirm that this morning was on sale at Oxford Street.
"No one is hurt and the police are investigating. Trading continues to trade normally."
Detective Conservative Tom Aylward of Metropolitan Police said: "This attack was a goal and lasted for a few minutes.
"My team is busy collecting witness accounts and recovering vital recordings of the store breakdown and suspect who have left the scene.
"Fortunately, no one has been hurt.
"I'd love to like those who were at that time in the area and see individuals, either at the venue or by fleeing, getting in touch with the police, and sending us the pictures and footage that we have.
"All suspects were men, we are still trying to find a full description at this time."
They are not arrested.
Anyone with any information asked to contact the police at 101.