From the Gov.uk website:
The Foreign and Commonwealth Office (FCO) against all but essential travel to the regions that the Spanish Ministry of Health have designated as areas of community transmission of coronavirus, as follows: Madrid and La Rioja, and the municipalities of La Bastida and Vitoria (both in the Basque Country) and Miranda de Ebro (in Castilla y León) ('Health' and 'Summary' pages)
https://www.gov.uk/foreign-travel-advice/spain