International mail from Morocco was carried out by foreign postal systems under contract. French, Spanish, German and British post offices established agencies in the country’s main towns.
The British post offices were run by the Gibraltar post mistress. She had Gibraltar stamps overprinted “Morocco Agencies.” In 1907, control of the British post office agencies in Morocco was transferred to London. Current British stamps overprinted “Morocco Agencies” replaced the Gibraltar stamps. The first stamps were overprinted in Spanish currency and issued on 1 January 1907. From 1917 stamps were overprinted in French currency for use at agencies in towns where the French currency was in use.
Stamps without a value overprint were also introduced in 1907. These were applied directly to postal items by the post office staff. Because these stamps would not leave the postal system, there was no need to overprint them in local currency.
In 1924, Tangier was declared an international zone. Spanish currency stamps overprinted “Morocco Agencies” had been used in Tangier as had the stamps without the currency overprint. From 1927 stamps were overprinted “Tangier” for use at the British agencies in that zone. Until 1949 such overprints were limited to the lowest values.
On 1 April 1957 the current set of stamps were overprinted “1857 – 1957” to celebrate the 100th anniversary of the opening of the British post office and the closure of the last office at the end of that month.
In 1950 British stamps with overprints that did not change the face value were permitted for use in the UK.