Generally, correspondence originating from government agencies will be sent free of postage. I always thought that this meant that ‘nobody’ paid for this but this was not the case. The Government had a contract with the P.T.T. stipulating that the P.T.T. would handle the Government’s mail at a reduced price.
Through accurate bookkeeping, the Government kept track of all such mail and then paid the P.T.T. accordingly. This system started in 1876. However, not all Dienstpost was paid for by the Government agencies. If, for example you contacted one of these agencies asking for some kind of personal information it could well be considered to be a private matter. In that case the requestor is asked to pay for the reply (Figure 1.).
By sending the response in an official envelope, but with the text AAN PORT ONDERWORPEN DIENSTBRIEF pre-printed in red on it the receiver is asked to pay for the postage. Since the requestor could not know how much to pay he will only be charged the regular postage and not double the amount which would usually be the case for a postage due item.
In the example shown in Figure 1 (a letter sent January 9, 1956 from ‘s-Gravenhage city offices to a local address) the postage rate for local mail was 7 cent, and that is the amount, and not 14 cent, the receiver had to pay in order to be handed the letter.
Undoubtedly there was confusion about the amount of postage due on these Aan Port Onderworpen Dienstbrief letters, so some agencies with a lot of this kind of mail decided to help the P.T.T. employees (and also make it look more official to the receiver of the item) by indicating the amount of postage due on the outside of the envelope.
Figure 2 shows a 1931 letter sent from De Ambtenaar van het Openbaar Ministerie bij de Kantongerechten te Roermond (Prosecutor of the District Court in Roermond) to Eindhoven. In 1931 the letter rate for a domestic letter was indeed 6 cent.
For a short period of time, from March 1, 1921 till January 15, 1923, there was no Aan Port Onderworpen Dienstbrief ruling, so, during that time a Dienstbrief to a private party was charged with double postage due. Figure 3 shows a letter of the second weight class (15 cent rate) sent October 11, 1922 from the Rijkswaterstaat in Eindhoven to Geldrop. The postage due in this case was two times 15 cent or 30 cent.
The Rijkswaterstaat is the government agency responsible for the practical execution of the public works and water management, including the construction and maintenance of waterways, roads, flood protection and flood prevention.
References
- Henk van de Laak: http://www.laakland.nl/portvrijdom_rws.htm
- L. Goldhoorn. Van een halve cent tot één gulden vijf en zeventig, Po & Po. Posthistorische Studies VI. 1979.