Since 2001, some adult British passports were issued with a validity longer than 10 years. This is because if you renewed your passport before it expired you were allowed to have the time left on your old passport added to your new passport. The maximum validity period possible was 10 years and 9 months. This means that you cannot rely on using the expiry date to check if your adult passport will be valid under the new Schengen* Border Rules (see list of countries below). From 10 September 2018 extra validity was no longer added to British passports and the maximum validity for a new adult British passport became 10 years, and for a child passport it was 5 years. This change was made to follow recommendations set out by the International Civil Aviation Organisation and to help provide clarity about passport validity in the future.