The Foreign, Commonwealth & Development Office has recently updated their guidance for the entry requirements for the Schengen Area (EU). A UK Passport must be:
• valid for at least 3 months after the day you plan to leave the Schengen Area;
• less than 10 years old.
The 3 months validity that is required when leaving a country must be within 10 years of the passport issue date.
Passports that were renewed before the previous one expired, will have had extra months added to the expiry date. The additional months on the passport taking the expiry beyond 10 years may not be counted towards the minimum 3 months needed. UK Emergency Travel Documents are accepted for transit and exit from the Schengen Area.
Further information for the FCDO guidance for foreign travel can be found at: https://www.gov.uk/foreign-travel-advice