Only 13 of the 1948 Gandhi 10-rupee Purple Brown and Lake 'Service' stamps are in circulation. The block of four was sold to a private Australian collector for the highest ever price for Indian stamps, said UK-based dealer Stanley Gibbons.
The Indian stamps were particularly rare owing to the fact they were in a set of four.
From the issued sheet, supplied to the Governor-General's Secretariat, only thirteen single examples are authoritatively recorded, including this strip of four and a block of four in the Royal Philatelic Collection, owned by Queen Elizabeth II, which is believed to be the world's largest and most valuable private stamp collection, Gibbons said in a statement.
However, the record price for a stamp sold an auction is USD 9.5 million (7.4 million pounds).
"The market for high-quality Indian rarities has been strong for several years and is supported by the ongoing desire of the wealthy Indian diaspora and savvy international clients to own these historic assets," Keith Heddle, managing director of investments at Stanley Gibbons, was quoted as saying by BBC.