Martin Lewis is urging motorists to check their driving licence is still in date - or risk a £1,000 fine.
Writing in the latest MoneySavingExpert email, he warned how two million drivers have photocard licences that are no longer valid.
The MSE founder said: "Photo driving licences usually expire after 10 years... If you don't renew, you ultimately risk being fined."
Fines for out-of-date driving licences can be up to £1,000.
Photocard licences replaced paper licences in 1998 and must be renewed every ten years.
This is not just to do with road safety - it's more about catching people driving illegally.
Renewing your licence means submitting a true-to-life photo of yourself, as yoour appearance will change over the course of ten years.
Doing this helps the police spot drivers using the wrong licence.
How to check and renew your driving licence
The Driving and Vehicle Licensing Agency (DVLA) should send you a reminder letter around one month or so before your current licence expires.
This should be your call to action to start the renewal process.
You can also check the expiry date printed on section 4b on the front of your photocard.
Once you have completed your renewal, your new licence will be valid from the date your application is approved - not from the expiry date of your current licence.
There are several ways to renew your photocard licence - online via the Gov.uk website, by post or in person at select Post Office locations.
It costs £14 to renew your driving licence online, or £17 if you renew by post.
If you do it at the Post Office, there is an additional £4.50 charge to take your photo and post your application as well.
Once you reach the age of 70, you need to renew your driving licence every three years - but this is free to do.
We’ve reported on pensioners that have fallen victim to third-party websites that are charging up to £80 to send your application on to the DVLA.
The DVLA has advised older drivers not to use these websites.
What happens if my driving licence has already expired?
You won’t get a fine for renewing your driving licence late - but the DVLA says you shouldn't drive until it has received your completed renewal application.
If your licence expires while your application is being processed, you can continue driving as long as you meet certain conditions.
This includes only driving vehicles that were previously allowed to drive.
You can also carry on driving if you've not being told by a doctor or optician that you shouldn't drive, and you aren't disqualified from driving.
Drivers have also been warned they could face a £5,000 fine or even prison if their vehicle is too messy.
