This GBD pipe from the 1950-70s is undoubtedly worth attention and may become a great addition to every pipe collection! Unique shape (such an interesting and very GBD-specific interpretation of a pot), pespex stem (another one GBD innovation!), "Collector" stamping refers to larger than usual pipe's size. The "Century" series was introduced in the 1950s when the company celebrated its century anniversary - many other manufacturers would call such the series a "Jubilee".
The pipe markings are "Collector \ (GBD) \ CENTURY", "LONDON. ENGLAND \ 9635". The length is 13.9 cm (5.47"), bowl's height is 4.9 cm (1.93"). External diameter of the bowl is 4.3 cm (1.69"), internal diameter is 2.3 cm (0.9"). The depth is 4.1 cm (1.61") and this pipe weights 48 gr. Briar, perspex stem, no filter.