Housed deep in the recesses of St James's Palace in London, the Royal Philatelic Collection is regarded as the finest and largest assemblage of British and Commonwealth stamps in existence.

The exact number of stamps in the collection is unknown, although it runs into tens of thousands. Highlights include a number of collectible British issues from the early 1840s and the extremely rare penny and two pence 1847 Mauritius specimens, which were the first stamps issued by a colonial post office. Bought by George V for £1,450, the unused two pence item would be worth millions were it ever to emerge at auction. A two pence cover sold for $4m in 1993.

The collection stems from the passion for stamps of Prince Alfred, Queen Victoria's second son. Alfred was given panes of the forthcoming 6d stamps in 1856, which started the future Duke of Edinburgh on the philatelic road.

Upon his death in 1900, the collection was sold and passed between members of the Royal family, many of whom also became keen philatelists.

It is thought that George V spent three days a week with his beloved small portraits of his own family, amassing 328 albums in the process. Ownership of the collection has now passed to the Queen.

Just six keepers have overseen the collection since the 1890s, helping to manage the vast number of stamps and arranging the exhibitions.

The collection includes an 1847 Mauritius two penny

The collection is a continual work in progress. The keepers have amassed mint items from all Commonwealth countries as well as occasionally splashing out on rare historical specimens.

Although the collection is not available for public viewing, an annual exhibition of rare specimens is displayed at the Royal Philatelic Society in London, while many items are often donated to special exhibitions throughout the country for collectors and investors to ogle .