A new investigation has found that more than 900,000 drivers risk a £1,000 fine for failing to renew their photocard licences.
Driver and Vehicle Licensing Agency (DVLA) figures obtained by the PA news agency found that 926,000 people had out-of-date photo cards as of September 3.
These figures represent two percent of all drivers in the UK although a small proportion are likely to have stopped driving without notifying the DVLA.
It was also found that 2.5 million drivers renewed their photocard after it had expired or within 56 days of the expiry date in the past year.
The DVLA says it writes to people 56 days before their licence ends to remind them to renew, but some drivers miss these letters as they do not update the agency when their address changes.
Driving entitlement normally remains until someone reaches 70, after which they must renew their licence every three years to stay on the road.
But photocards must be renewed every 10 years to ensure the image is a true likeness of the driver. Expiry dates are displayed in section 4b on the front of cards.
Failing to return an expired licence to the Driver and Vehicle Licensing Agency (DVLA) is an offence under the Road Traffic Act 1988 and can be punished with a fine of up to £1,000.
Renewing late does not lead to a fine being issued. If a licence expires while the DVLA is processing a renewal application, the person can continue to drive as long as they meet criteria such as following the rules of their previous licence.
After a photocard is surrendered, someone who drives without renewing their licence could be prosecuted for driving otherwise in accordance with a licence.
Philip Gomm of the RAC Foundation said: "There are good reasons to keep licences up to date, beyond the basic legal requirement. They are also a widely accepted form of ID and will certainly be required if you are ever stopped by police.
"Renewal also provides an opportunity for people to assess whether they are still fit to drive, and we think there is an argument for linking a compulsory eye test to the process to make sure we all remain safe on the road, though Government should help keep costs as low as possible for motorists."
The DVLA advises people to renew on its official website as it is the quickest and cheapest method. Applications cost £14 and are usually processed within five days.
Postal renewals cost £17, while doing it at a Post Office has a £21.50 fee. Third party websites charge additional fees.
A DVLA spokeswoman said: "We encourage customers to use GOV.UK as applying online is the quickest and cheapest way to renew their photocard driving licence.
"If you stop driving altogether, you should inform DVLA and return your licence rather keeping it as a form of out of date photo ID."
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