There is no universal age limit imposed by the UK government for driving abroad on a valid UK photocard licence. Your entitlement to drive is based on the validity of your licence and the categories it covers, not your age.
However, restrictions often come from two other sources:
Some countries impose minimum or maximum driving ages for foreign licence holders that differ from their domestic rules. For example, certain nations may require drivers to be over 18 or 21, regardless of the UK licence minimum age (17 for cars). Always check the specific regulations of the country you are visiting via their embassy or a reputable motoring organization (like the RAC or AA).
This is the most common hurdle. Rental firms set their own age policies, which vary significantly by country and company:
Bottom line: Your UK licence itself doesn't expire due to age (until 70, when renewal requires a medical self-declaration), but local laws and rental contracts might.