Webley Junior Pre War - Earliest Known Model.
Courtesy of Leonardj.
This Junior bears the SN of "J121", which is described by M. H. Newcomer, in Part III of his article on Webley Air Pistols, back in the June 1978 issue of Guns Review, as being the "earliest known Junior".
Another reference to this same Junior can be found in the 3rd Edition of the book Airpistols, by Dennis Hiller.
Webley Junior (cased prewar tin grip)