Judging by the saddle, the headclip headset, the derailleur mount on the chain stay, and the Hans Ohrt bike shop sticker, the bike was probably built in the 30's or 40's. The seat post and stem are probably be original, but I have my doubts about the rest. The crank is a Rudge crank, but appears to belong to a lower end model of bike.The brakes are certainly much later. Apparently it once had a dropout-mounted derailleur as well.
The fork looks like a Rudge fork, but with round blades, which is unusual. The tabs on the seat stays are for a rear mudguard, so it is odd that the fork doesn't have them; perhaps it is not the original fork.
You can find a 1939 Rudge catalog here:
http://threespeedhub.com/wp-content/...og_1939_UK.pdf
I see there was a model called the "Olympic Road" (no 92) which would match the seat tube decal.