An ounce of knowledge is worth a pound of guesses....

This is a frankenbike with a high quality British or French frame maybe from the 1950's???

Serial numbers tend to be red herrings...

The lugs are Nervex Serie Legere Model 48/161 with 158 nozles. These were not very commonly used. (Maybe Oscar Egg on an earlier frame???)



The fork crown looks like a reworked Wagner???



The seat stay eyes required a lot of work so that indicates quality.



The headset appears to be a TDC Continental Prima which was the top British model from that era. That narrows it down to a British frame. The GB bars and stem are British to but from the 1970's.



Allowing for paint thickness, on a British frame the top tube should be ~25.5mm to 25.6mm, the seat and down tubes 28.6mm to 28.8mm. A 26mm+ top tube would be metric, indicating maybe French.

What size is the seatpost? 26.8mm, 27.0mm or 27.2mm would indicate lighter gage tubing, perhaps Reynolds 531.

There were dozens of small builders in the UK. You may never find the actual builder. Just consider it a "barstard" and enjoy it.

One odd thing (among many) is the drilled hole and cutaway on the Simplex front derailleur cage. Another is what looks like a broken off tang of some kind on the bottom bracket????

verktyg