Spanish Residency for British Nationals
British citizens / UK nationals now have to follow the same process as other non-EU national citizens of third countries to get Spanish residency, i.e. first obtain a visa.
The minimum income required for a British Citizen / UK national to obtain a residency visa, is a lot higher than it was to get residency before Brexit. In most cases a single applicant needs to have at least €28k per year, whereas previously less than €7k income would have been sufficient.
You also have to obtain a police criminal check report, and medical certificates are also required for most visa applications.