The auction will comprise material duplicate to the archive collection, with proceeds to benefit the new home of The British Postal Museum & Archive, which will be situated at Calthorpe House on London's Mount Pleasant site and is scheduled to open in early 2016. In the July sale, collectors will have a choice of selected issues from the reigns of King George V (Seahorse issues), King Edward VIII and King George VI (definitive issues). The auction comprises 191 lots and is estimated to bring in excess of £5 million.

Commenting on the collection of stamps to be offered, Richard Ashton, Sotheby's Worldwide Philatelic Consultant, said: "This selection of material from The British Postal Museum & Archive includes numerous items that are of the utmost rarity. Now in my 50th year as a professional philatelist, I have never seen such an important sale of its type. Many are the only examples of their kind ever to come on to the market. Quite aside from their rarity, these extraordinary stamps are also of great beauty - engraved to the highest standard by leading masters of the day. Collectors will never again be presented with such a unique opportunity."

KING GEORGE V - The "Seahorse" Issues, 1915 to 1934 (Lots 1-12)
The "Seahorse" Issues, 1915 to 1934 are considered to be the finest stamps ever produced by Great Britain. The balance of design and the superb printing techniques employed converged to produce a series that is immensely popular with collectors. Designed by Bertram Mackennal with lettering by George W. Eve, the master die was engraved by J.A.C. Harrison. The "Seahorse" high face value stamps were in use for twenty-six years and involved four contractors. Variations in the paper, a plethora of shades and many different printing plates shaped their development during this time. The printers devoted much attention to the printing plates and this resulted in a host of re-entries, which are highly prized.

KING EDWARD VIII - Definitive Issues (Lots 13-40)
King Edward VIII ascended the throne on 20th January 1936. A few days later, the Post Office took the first steps in preparing designs for the postage stamps of the new reign. The designer of the iconic issue has been acknowledged as Hubert John Brown and a very poignant story regarding the design emerged in the years that followed. H.J. Brown recalled how, when sitting an examination at the age of eighteen in 1936, his thoughts strayed and he began to wonder what sort of stamps there should be for the new reign. He sketched a rough design and submitted it to the Postmaster General.

A letter of acknowledgement was received by return with the comment: "I should perhaps mention, however, that the design is usually chosen from the competitive designs of distinguished artists." The King rejected all the designs for the stamps save one which was, in fact, the design submitted by Mr Brown. Though certain adjustments were made, the issued stamp was essentially the work of Hubert Brown. The establishment was thrown into crisis with the King's abdication and only following extensive publicity in the press was a begrudging acknowledgment prised from the Post Office confirming the identity of the young designer of the new stamps. Sotheby's met with Hubert Brown in 1998 and his original sketches and archive were offered by the company in July 1999. Mr Brown passed away in December 1998 and is fondly regarded as a man who broke the staid mould of British stamp design.

Four values in the design were issued and Sotheby's sale includes a single set, sets in pairs and blocks of four, and a set in blocks of six which have the printing Cylinder number. The star lot in this section is a set of four Registration blocks of 48, estimated at £100,000-120,000 (lot 18). Also on offer are blocks from the special Booklet panes of six in various forms, a similar range of Coil stamps, produced for use in vending machines, and the Postage Due issues from 1936 to 1937. Lot 40 comprises a unique collection of King Edward VIII issues, essentially 'one-of-each' from this reign, offered with a tempting estimate of £20,000-25,000.

To read the complete article, see:Sotheby's unveils the contents of Sale of Duplicate Stamps from The British Postal Museum & Archive in London(artdaily.com/index.asp?int_sec=2&int_new=62597#.UZVzjLWNqXg)