The brake mechanism that can be seen in the centre of the sidecar wheel is the so-called Douglas disc brake and often claimed to be the first disc brake. Although similar in appearance at first glance to a modern disc brake, close examination shows that the "caliper" is in fact just a hollow steel shoe which presses onto a friction material wedge shaped disc. The sidecar brake is probably linked to the motorcycle brakes. I have not looked at it as closely as I shall next time I see it in September. The long hand operated lever is the sidecar passenger operating handle to control the sidecar banking mechanism. Yes! this is the famous Douglas banking sidecar which allows faster cornering. The outfit (a replica) is currently in the Beaulieu Motor Museum in The New Forest, Hampshire. The motorcycle is a genuine RA model and was owned by the late Bob Thomas. In the terms of his will it was left in trust to the Isle of Man where he lived for the latter part of his life. The banking sidecar is owned by the motor museum. A placard on the machine referring to loan of the RA by Bob Thomas was changed upon his death and the loan is now credited to The Trust.
