$479,300 for 'one of the finest Penny Black plate number stamp pieces'

Blocks of Penny Blacks (the world's first adhesive postage stamp from 1840) are rare. But plate blocks are even rarer...

And a plate block of four Penny Blacks in mint condition is about as good as it gets for many stamp collectors and alternative investors.

Which explains why a plate block of four Penny Blacks from plate seven sold for £300,000 ($479,349) in part two of Spink's Chartwell Collection auction in London, today (June 29).

A rare Penny Black plate block

Spink states that the lot's "outstanding freshness and quality" ensures "this is without doubt one of the finest plate number pieces extant."

Arriving at auction with an estimate between £300,000 and £350,000, this breathtaking specimen is the only known plate number example from plate seven.

It comes from the lower left of the sheet, enabling the plate number and marginal inscription to be in evidence. The inscription reads: "PRICE 1d. Per Label, 1/- Per Row".

It also features the full original gum, and two light diagonal gum creases.

The stamp didn't quite hit its low estimate - although it did have to jostle for space alongside the 'finest and most attractive Penny Black cover in existence,' which sold for nearly $0.56m.

There are more results to come from Spink today, so make sure you check back here shortly.

Join our readers in over 200 countries around the world - sign up for your free weekly Collectibles Newsletter today or download our free Collectors News app for your iPhone