With thanks to impactcycling forum for pointing it out..
I initially thought "ridiculous" but then warmed to the idea. There were somewhat larger but still small indoor velodromes during cycling's hey-day in Sydney early in the 20th Century, like the (140m?) Surry Hills board track (later moved to Canterbury before being added to the current horse racing reserve). And reportedly an even shorter and steeper(100m?)track in an old shed at Carlton near Hurstville. Some people believe that the shed still exists as an art supplies shop - and whilst I can visualise it (I've been there to check it out) it can't have been even 100 around, surely, and it must have reached the roof to get enough banking... perhaps it was just a bit bigger than this new London one... which is 25m!!
A hot lap is around 3.2 seconds or so... and the trick is to ride smooth with constant pedal pressure and stay low on the banking.
Anyone for a sprint?