GB Overprints Society

Cachets, postmarks and other markings that look like overprints

Items which pass through the post acquire a huge variety of markings in their journey. These are usually applied to the letter or packet but occasionally find their way onto the stamp and can look remarkably like overprints. This often happens, for example, to ship letter cachets used on Paquebot items, which have sometimes been used to cancel (or just to adorn) the stamp.

In a slightly different category are official postal cachets for exhibitions, expeditions etc, which were meant to be applied to the postal material but were deliberately used by the organisers to cancel the stamps in a way which looked like an official overprint.

Some commercial overprints have been mistaken for overprints. In some cases their ambiguity has even led to them finding their way into postage stamp catalogues: see, for example, Australia and PSNC below.

Note: this numbering system was drawn up by the Society for the website, and may not be used without permission.


Stamps are known with a "CA" overprint, which is assumed to be probably a commercial security overprint either from Crown Agents or Australia House ("Commonwealth of Australia"), though this is still uncertain. What is certain is that they were not an "official" stamp in the way that "IR Official" and other overprinted stamps were used: apart from anything else they first appear after the use of departmental officials had ceased.

CA overprint 96
(image courtesy of Stuart Sawyer)

1 1d red, King Edward VII, De La Rue printing, dates unknown

2 6d violet, King Edward VII, De La Rue printing, ordinary paper, dates unknown

CA G5 half penny 200

(image from unidentified magazine clipping) 

3 ½d green, King George 5, Downey Head, watermark crown die 1A or IB, dates unknown

4 1d red, King George 5, Downey Head, watermark crown die IB, dates unknown


Colombia 200

Between 1921-23 (other reports say 1921-26) semi-official airstamps of the German/Colombian airline "Sociedad Colombo Alemana de Transportes Aéreos" (SCADTA, later "Avianca", ie "Aerovías Nacionales de Colombia") were sold at Colombian consulates around the world to prepay air postage within Colombia on mail received from abroad, overprinted with a large handstamped abbreviation of the Spanish name of the country from which individual items were to be flown. For Great Britain the overprint was "G.B.", giving the unique categorisation of a "foreign stamp overprinted for use in GB" - the opposite of a "GB stamp overprinted for use elsewhere" but an interesting fringe item nonetheless.

Gibraltar, Las Palmas

Two "overprints" have been reported for Gibraltar, though they are probably not.

Gibraltar cachetLas Palmas cachet 200

(illustrations: Gibraltar courtesy of Colin Searle, Las Palmas courtesy of Mark Topping)

1 A 1d Edward VII stamp with a diagonal "Gibraltar" is probably a ship's cachet to accompany a paquebot item, though it is applied very neatly on the stamp rather than on the envelope as is more normal.

2 A similar ships cachet for Las Palmas

3 The Overprinter 2/2000 illustrates a "GIBRALTAR" overprint on a 2/6d castle stamp in large block capitals (39mm * 6mm) across the whole stamp width. It is not part of any known postal marking so is probably a local political propaganda artifact as a part of a "Keep Gibraltar British" campaign.

Gough Island, Enderby Land, Tristan da Cunha

Tristan 300

Gough Island 200

(Gough Island illustration from unidentifed magazine article)

Stamps which appear to bear a rectangular overprint "Gough Island", "Enderby Land" or "Tristan da Cunha" are in fact merely cachets from the Shackleton-Rowett Antarctic Expedition of 1920-22.

In The Overprinter November 1974 it is reported that Sir Ernest Shackleton, appointed "Agent of the Postmaster-General" for the trip, was given stamps including a sheet (40) each of 2/6d, 5/- and 10/- Seahorses, and cachets for Gough Island, Tristan da Cunha and Enderby Land (also referred to as Enderby Island in some earlier sources, though the current name is "Land" to avoid confusion with Enderby Island just south of New Zealand). However it is reported that these cachets were not used, though normal postmarks were. There was therefore official post office sanction for this issue, but only as a cachet not an overprint. The illustrations in Crabb's book prove this since when on cover/piece the cachet is often partly on the envelope ("The History and Postal History of Tristan da Cunha", Ewell, 1980). It is interesting to note reports that the original request was for actual overprinted stamps, modelled on the New Zealand "Queen Victoria Land" and "King Edward VII Land" overprints for the New Zealand anntarctic expeditions (the latter also led by Shackleton).

The article in The Overprinter implies that few copies other than one 10/- Seahorse still exist. Other values are reported to exist with this cachet (over 2 stamps in the case of low values), including 1d and 2d stamps. An example of the Tristan cachet on a pair of 2d George V British stamps is illustrated in the International Encyclopedia of Stamps. The Tristan cachet on a pair of 6d stamps is illustrated on the 1971 Tristan da Cunha set commemorating the 50th anniversary of the expedition. Further illustrations of the cachets and examples on cover are in G Crabb's book on Tristan da Cunha. These items are keenly sought after, more by postal history collectors than overprint collectors, though they are often misdescribed as "overprints". For a fuller history of these items see Gibbons Stamp Monthly article, which illustrates examples on ½d, 1d, 1s, 5s and 10s stamps.

Gough Island is some 360 km Southeast of Tristan da Cunha; the expedition did not actually reach Enderby Land).

Further Tristan "overprints" are included under "phantoms"

Great Britain: officials

"OHMS" on King Edward VII, King George V

GB G5 OHMS 200

1 Copies of various stamps are known with an "OHMS" overprint. These are not official. According to an article in "The Philatelic Journal of Great Britain", December 1979, at least some of them were produced by government officials for use on their own mail back to the office: "there is some evidence that at least one Department overprinted or handstamped the stamps ... with OHMS." (Ivan F. Trinder; article by courtesy of the Librarian of the GB Perfins Society). The ½d die II illustrated above is from this article, which continues "The overprint is in deep purple, and it is thought was used by an official while on holiday at Llandudno on the 22nd August 1913".

2 The King Edward VII "O.W. Official" ½d stamp is known with an (inverted) "O.H.M.S." overprint in thick block capitals. This is somewhat strange given that the "O.W. Official" overprint already indicated the mail was official. For the same reason it is unlikely that the OHMS overprint was a protective overprint (akin to a perfin), since the "O.W. Official" overprint should have been sufficient security against theft. The purpose on this stamp remains obscure.

"ARMY H.M.S.": King Edward VII

Oliver and Vallencey record a rubber handstamp "ARMY H.M.S." on the ½d Edward VII "but the actual status of the overprint is doubtful". It probably arose in similar circumstances to the "OHMS" overprints described above. ("The Postage Stamps of Great Britain 1840-1922", London 1923)


The overprint recorded on a 5d King Edward 7 stamp (The Overprinter 1/2004) appears to be a handstamped cachet from a receiving office, so is nearer in origin to the "Gibraltar" item mentioned above. "Guyane" is French Guiana.

Pacific Steam Navigation Company

PSNC 200
(image courtesy of Cavendish Auctions)

1d lilac overprinted "P S N C", presumed to be a security overprint by the above company (whose initials also appear, for example, on the first issue of Peru in 1857). These sought-after stamps survived in a bottom marginal mint strip of 4 (Cavendish auctions 5 June 2003), though this appears to have been rather vandalously split into a pair and two singles for an auction in 2005.


6d Jubilee stamp with a diagonal cachet "TRANSVAAL", probably part of a receiving cachet or some office handstamp (cf "Gibraltar" above). Or maybe a totally bogus attempt at an overprint.

Transvaal 300

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page last updated: 2 September 2006, 4 March 2013 

gbos: GB Overprints Society