Many Britons who have been living a long time in Spain are so worried about their situation after Brexit that they are applying for Spanish nationality, despite the fact that there is no dual nationality treaty between the two countries. By doing this, people feel that they will be able to conserve the rights that they are in danger of losing.
Two EuroCitizens members have prepared a table detailing the steps that you need to take in order to apply for Spanish nationality, which we hope will be of use. We are not lawyers and cannot give any advice about whether or not you should make the application. That is up to individuals. What we are doing is lobbying for the introduction of dual nationality for Britons in Spain (Spanish citizens in the UK can get dual nationality).