The gov.uk foreign travel advice pages are the most straight forward ish , these rules have been in place since we left the EU but incidentally do not apply to many/most non EU countries so check each country’s page on gov.uk for the correct advice

If you are planning to travel to an EU country (except Ireland), Switzerland, Norway, Iceland, Liechtenstein, Andorra, Monaco, San Marino or Vatican City, you must follow the Schengen area passport requirements.

Your passport must be:

issued less than 10 years before the date you enter the country (check the ‘date of issue’)

And valid for at least 3 months after the day you plan to return home (check the ‘expiry date’)

Even then I’ve changed the wording slightly on the return home bit to make it clearer


Hope this helps