Unfortunately if it is a UK Passport with a red cover this does not make any difference. UK nationals no longer have freedom of movement within the EU. If you wish to apply for a Spanish Visa the Spanish Embassey or Consulate (there are currently 3 locations in the UK that deal with visa applications: London, Manchester or Edinburgh) who will deal with your application is based on your current UK place of residence. The link below will help you to determine which location applies to you
May I add it is always best to follow official guidance and not that which is posted here as the authors (including me) may not be best placed or up-to-date with current instructions/procedures: