Spanish Taxation - Withholding tax
Dividends paid by Santander will (under current law) be subject to Spanish withholding tax at the rate of 18% on the gross dividend paid.
If you are a UK resident you may also be subject to UK tax on dividends paid by Santander. The dividends will not carry a tax credit. Credit will, however, generally be given for the Spanish withholding tax of 18%. You will be sent dividend statements giving you the necessary details so you can claim this credit in your tax return.
Click here for full information on Spanish withholding tax.