1881: Surface-Printed 1 penny lilac, die II, Crown wmk., perf. 14, good colour and fine perforations, tied by the barred oval “A01” to an envelope sent to London, with handstamp “4d/F.B.” charge mark in black and alongside small triangle “FLB / 3” in purple. Reverse, an arrival cds "LONDON “W.C. AU 9 01”. A few tone spots, which don't detract. Fine and interesting example of a British stamp used abroad and unaccepted.
Note: The “A01” was previously assigned to the British PO in Jamaica, but redeployed to the Foreign Branch in the UK, and used by inspectors from early 1900s. The country of origin did not mark the cover as unpaid, although it had to have been put into the postage due mailbag or wrapper to be noticed and charged at the London Foreign Branch for an improper use of a British stamp abroad.
Reference: Illustrated in “Collectors Club Philatelist”, New York, Jan./Febr. 2011