If you exceed the time limits for visitors from third countries (now includes the UK) you may be fined or even removed from Spain.
Being found irregularly in Spanish territory, due to not having obtained the extension of stay, lacking a residence authorization or having a residency document that has expired by more than three months (provided renewal has not been applied for within the time period specified) will all be considered serious immigration offences.
Also an offence is working in Spain without authorization and without a residency document.
Serious offences incur fines of 501 to 10,000 euros and may carry expulsion from Spain. Fines and expulsion may not be imposed jointly. Expulsion may not be valid for more than five years.
Although, currently, Immigration may not be aware when someone has exceeded the 90 day rule, the new EES system (described above on this webpage) is expected to change this and will probably come into force in the first three months of next year.
