Whilst we do not provide immigration advice, please see below official guidance per country:

 

United Kingdom 

https://www.gov.uk/ancestry-visa

https://www.gov.uk/british-passport-eligibility

 

Republic of Ireland 

https://www.citizensinformation.ie/en/moving-country/irish-citizenship/irish-citizenship-through-birth-or-descent/

 

The Netherlands

https://www.netherlandsworldwide.nl/dutch-nationality/becoming-dutch-national-abroad

 

Germany

https://uk.diplo.de/uk-en/02/citizenship/acquiring-german-citizenship-2463622

 

Portugal

https://www2.gov.pt/en/cidadaos-europeus-viajar-viver-e-fazer-negocios-em-portugal/viver-em-portugal/obter-nacionalidade-portuguesa

 

Greece

https://www.mfa.gr/uk/en/services/greek-citizenship/citizenship-through-naturalisation-for-aliens-of-greek-ethnic-origin.html

 

Denmark

https://storbritannien.um.dk/en/travel-and-residence/danish-nationality/danish-by-birth

 

Norway

https://www.udi.no/en/word-definitions/norwegian-by-birth/

 

Sweden 

https://www.migrationsverket.se/en/you-want-to-apply/swedish-citizenship/citizenship-for-adults/citizenship-for-adults.html#svid12_2cd2e409193b84c506a3054d

 

Switzerland

https://www.sem.admin.ch/sem/en/home/integration-einbuergerung/schweizer-werden.html

 

Spain 

https://administracion.gob.es/pag_Home/en/Tu-espacio-europeo/derechos-obligaciones/ciudadanos/residencia/obtencion-nacionalidad.html

 

Hungary 

https://hungariancitizenship.eu/procedure/

 

France

https://www.service-public.fr/particuliers/vosdroits/F1051?lang=en