it says here (on tiniternet)...

In 1966, Don and a squad of 'minders' turned up at impresario Robert Stigwood's office to 'teach him a lesson' for daring to discuss a change of management with Small Faces. This became one of the most notorious incidents from the 1960s British pop business. Don wanted it to be like a scene from a gangster movie with Stigwood threatened with being thrown out of the window if he ever interfered with Don's business again.

Thanks, JK - remember the stranger the story appears to be the more likely it is to be true !