The pair worked together on LOCK STOCK + TWO SMOKING BARRELS and SNATCH before Vaughn made the switch from producer to director, first making Mean Machine and then LAYER CAKE.
Ritchie insists he was surprised and disappointed to lose his partner - and hasn't been overwhelmed by Vaughn's efforts behind the camera.
He says, "I didn't see it coming, Matt deciding to become a director.
"I haven't seen Layer Cake in its final form but I saw two earlier versions.
"I always thought it would struggle to make money but it was enjoyable. I would probably have done it differently. Made it more esoteric and probably a bit funnier."