“However, the vast majority of flats and villas cannot be offered for holiday rental, because the tourism authorities do not license them. And, even if official permission is sought, it is rarely granted.
“There are strict conditions before properties are approved for rental to holidaymakers,” says a spokesperson for the Spanish Ministry for Tourism. “Nearly all are not licensed, which means letting them to tourists is illegal.” “
I do not fully know the politics in Spain, but if it says that it is illegal, then it is illegal. The law in Spain should be as strong as the one in UK.
British people should obey Spanish rules when living in Spain.
The Telegraph does an excellent job warning people against buying BTL properties which are not allowed to let. I wish I could read much more such informative articles.