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The estimate was “on request” and the bidding opened at £200,000, with at least five bidders competing in the room before it sold on the phone.

The coin last appeared at auction in 1950, when it sold along with three others from the Grand Duke George Michailovitch collection at Christie’s for a total of £209 – the gold 20 roubles making up £145 of that sum.

The successful bidder then was Christie’s sales clerk Roy Davidge, presumably acting for a client, of whom it seems we now have no record.

St James’s state that these coins have remained in the same ownership since 1950. The hammer total for the four coins here was £1.78m.