A great photo dating from, by the looks of the bikes, the early thirties. The image is a professional one and quite sharp, for a bit of fun enlarge it and see how many of the bikes you can recognise in the line-up. Look closely and there is some quite tasty machinery in there.
It looks like the chaps were about to engage in something competitive from the attire and the number boards on the bikes. I say about to as the white coveralls some of the guys are wearing are still very clean! The bike on the far right seems to have Brooklands style streamlining fitted.