Conway Stewart No. 286 (Marbled Plum and Black)
The 286 model was produced between 1930-1945, though the design varied over this period and this appears to be a later model with a shorter barrel. At this age, it has not surprisingly lost its gold plating on the clip, but is otherwise in good shape. The 14kt gold nib appears to somewhat italic in the way it writes, though the tip is not chiselled as such.