I am still waiting on an answer as to why it matters if they stamp your passport.

Firstly, it would be helpful if passport control were made aware of the UK/Spanish agreement. Secondly, the method of calculation for the 90 days UK citizen allowance in Europe is slightly vague and linked to both the passport stamp and computer registration made at customs. You could argue this is a technicality, as referencing the British Embassy post (earlier) Brits can challenge the 'stamp' and have it removed. However, being all too familiar with the nightmare that dealing with Spanish/Mallorcan bureaucracy can present, I for one don't fancy that particular experience.

Lisa has a valid point. Residency in Spain is irrespective from where you are. Your passport is merely a form of ID, since the silly green card has no photo. No more, no less.

Why oh why does it matter if your passport gets stamped. Someone please explain.

My reference was a statement from the British Embassy in Madrid Jan 21, 2021 (13.41) Title "Brits in Spain". The rule is that UK nationals who can prove they are residents in Spain "should not" have their passports stamped when entering or leaving the territory. There are measures in place to have stamps "challenged" should any UK travellers be ignorant of the procedure. Thanks guys :)

UK Government advice:- "If you registered for residency before 6 July 2020 and have a green paper residence certificate, you do not have to take action. Your green certificate (A4 or credit card-sized) remains valid and proof of your rights under the Withdrawal Agreemenent. You may exchange it for the new TIE if you want to." https://www.gov.uk/guidance/residency-requirements-in-spain

@Lisa. The fact you don't seem to know the difference between immigration and customs says a lot.

The purpose of stamping the passport is to record the date of entry to/exit from Spain so that it can be established how long non-residents have stayed, as their presence in the country is limited by law. Residents are not limited in their length of stay, and consequently do not need their passports stamped. My wife and I have never had our passports stamped at Menorca airport, we just have to show our TIE cards and British passports. I believe any other procedure is neither lawful nor sensible.

What has the British Embassy got to say about this ?

@Lisa As far as I understand it they should in fact stamp your passport. The passport is your travel document where your TIE card is your ability to enter Spain/EU without restriction. They are two very different things. As UK citizens are from a 3rd country the policy should always be to stamp the passport. I'm from a 3rd country and I have always gotten my passport stamped.