DISRAELI GEARS
This is one of two derailleurs in this collection that :
This example has a very beautifully made and finished steel parallelogram, with what look like high quality small parts. At first sight I guessed that it might be a genuine Campagnolo parallelogram - but, crucially, the p-knuckle does not have the typical pulley cage rotation limiting screw. The pulley cage is something else - it is aluminium and the outer plate has a shape that I have never seen on anything made by Campagnolo. The pulley wheels look like Campagnolo items from the late 1960s, but they have no writing on them. Finally the chroming and detailing on the main b-pivot and p-pivot Allen bolts is not typical of Campagnolo.
The derailleur looks and feels as though it would work very well - with one proviso. This is that the head of the guide pulley pivot bolt has been filed down so that it does not hit part of the p-knuckle.
I obtained this derailleur from the UK but I have no real idea who made it, or when or where it was manufactured.