Great Britain Philatelic Society

The attached image of stamp AF shows a strong vertical line adjacent to the NE corner. It is no doubt well known and documented in the literature especially Dr Osborne's work on this plate. As I do not have access to this I would be grateful if anyone could forward Dr Osborne's comments or those of any other authority.

This is a mid-sheet marker between AF and AG. It indicates where to divide the sheet in half vertically. There is another one at the bottom of the sheet (TF-TG). A horizontal line crossed the mid sheet marker and indicated where the sheet should be pinned for peforation. A fan-shaped ornament was used on the side to indicate mid sheet. This is discussed in the SG Specialised and the Postage Stamps of Great Britain but Osborne does not spend much time on marginal markings and does not present all of the above info.

Hope this helps.