An $8.3m (£6.2m) stamp is returning to the UK for the archetypal clip successful 143 years, aft being sold astatine auction to a British uncommon stamp dealer.
The British Guiana 1c Magenta was bought by uncommon stamp trader Stanley Gibbons past month.
The trader said that, gram for gram, the stamp is thought to beryllium the astir invaluable man-made point successful the world.
It is the lone subsister of a tiny batch printed connected the erstwhile British colony British Guiana, present Guyana.
The stamp, printed connected magenta insubstantial and measuring 29 x 26mm, bears a three-masted vessel and the colony's motto, "We springiness and expect successful return".
It went into circulation successful 1856, erstwhile a shipment of stamps was delayed from London and the colony's postmaster asked printers to marque 3 types of impermanent stamp until the shipment arrived.
Once it arrived, the postmaster ordered them to beryllium taken retired of circulation - but 1 1c stamp survived.
It was discovered astir 20 years aboriginal and returned to Britain for a abbreviated time, but was past sent to a postulation abroad.
On arriving astatine Heathrow Airport, it volition beryllium met by an armoured motortruck and volition spell connected show astatine Stanley Gibbons' store successful London successful a specially commissioned, zero-oxygen frame.
Graham Shircore, main enforcement of Stanley Gibbons, called it "the Holy Grail of philately".
"It's genuinely 1 of a kind, and we're delighted to beryllium welcoming it backmost connected to British ungraded wherever we anticipation it volition remain," helium said.
The trader intends to marque the stamp disposable to collectors done a shared-ownership scheme.
"This isn't conscionable for affluent collectors. We are processing a pricing exemplary that volition let anyone to articulation the club," helium added.
The stamp has been connected show astatine the Smithsonian National Stamp Museum successful Washington DC, connected indebtedness from its erstwhile owner, the US footwear decorator Stuart Weitzman.
It has marks from each of its erstwhile owners, including the authorities of France and John du Pont, who was convicted successful 1997 of murdering Olympic Gold Medallist David Schultz and died successful situation successful 2010.