Foreign home - Tax on income

[mywifeshusband]

I'm thinking of having a small house in Spain to live in for part of the year (maybe 2 or 3 months in total) and use as a rental income vehicle for part of the year.
I'm employed in the UK and am paid through PAYE.
I know the income from the property rental will be taxable but who gets to tax me?
(1) Spain as that's where the income is generated? Would there be a tax free allowance and what tax rate %?
or
(2) UK through Self Assessment as I'm a UK resident and tax payer already?
or
(3) Both countries want a slice of the action?

This is just thoughts at the moment but the answer will change the viability of the project to wash it's own face.

[mywifeshusband]

Thank you both, much food for thought.

[mywifeshusband]

Again many thanks for all the input. The rise to 24% mentioned above along with other factors puts a large shadow over the idea.

I also think most British in Spain have a unique idea of their status there. They see themselves as “Ex-Pats” not foreigners as they view foreigners in the UK. The Spanish are lucky to have them and they’ll only pop back to Blighty to use the NHS.
It takes all sorts...........