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So I phoned the SA Embassy in London again, only to be told that "the Germans can't tell us what to do". The woman told me to give power of attorney to my father in Cape Town to get this mysterious certificate that the Germans say they don't give out anymore.The document “Urkunde über den Erwerb der deutschen Staatsangehörigkeit durch Erklärung“ is a certificate which was issued between 1975 and 1977 to the children of German mothers married to foreigners, if those children were born before 1975. These children did not acquire German citizenship at birth due to the laws of the time. When the law changed in 1975, there was a two-year window in which women could declare they wanted their children to become German, and then this document was issued.
If you are German through your German father, this does not apply to you.
I regret to inform you that the German Embassy in London cannot issue letters to confirm when and on which legal basis German citizenship was obtained. German citizenship can only be confirmed by the competent citizenship authority, the Federal Administration Office (Bundesverwaltungsamt) in form of a certificate of citizenship (https://uk.diplo.de/uk-en/02/german-cit ... itizenship ). Please note that this certificate does not contain information on when and how German citizenship was obtained. The processing times vary, but usually take a minimum of one year or more.
The German Embassy in London is not a citizenship authority and can thus not bindingly confirm German citizenship. I am, however, happy to provide a leaflet containing information on German citizenship law. This document lays down in detail when German citizenship can be obtained by descent. When German citizenship is obtained by descent, this takes effect automatically at the time of birth, irrespective of when a German passport is issued.
The South African Embassy in London has been officially informed of this change in our procedure, which is in accordance with the practise of the German missions in South Africa. I regret to say the South African embassy does not seem to accept those letters anymore, as far as other bi-nationals in your situation are telling us.