Just copied this off the GOV.UK website which was updated 20 April 2022 still current 1 May 2022.
Check your passport and travel documents before you travel
Check with your travel provider to make sure your passport and other travel documents meet their requirements.
Passport validity
If you are planning to travel to an EU country (except Ireland), or Switzerland, Norway, Iceland, Liechtenstein, Andorra, Monaco, San Marino or Vatican City, you must meet the Schengen area rules.
Your passport must meet 2 requirements. It must be:
less than 10 years old on the day you enter (check the ‘date of issue’)
valid for at least 3 months after the day you plan to leave (check the ‘expiry date’)
We are asking the European Commission to clarify the 10-year rule. Their guidance for Schengen border guards may not be updated until the spring of 2022. Until then, for some Schengen countries your passport may need to be less than 10 years old during your whole visit, and the 3 months at the end of your visit may need to be within 10 years of your passport’s issue date.
Check both the issue date and the expiry date in your passport. If you renewed your passport early, extra months may have been added to its expiry date. This could affect the requirement for your passport to be less than 10 years old.
Contact your travel provider or embassy of the country you are visiting if you think that your passport does not meet both these requirements. Renew your passport if you need to.