Suffolk Police could have your licence revoked on the spot if you fail a roadside number plate test. 

The roadside vision screening asks drivers to read a number plate from a distance of 20 metres. 

All tests are done in good daylight conditions using a registration placed at the correct measured distance with the driver wearing any eyesight correction at the time of driving. 

This is because Suffolk Police are asking: 'Is your vision roadworthy?' as they want to highlight the importance of good sight whilst driving in the dark this winter. 

Under legislation known as Cassie's law, drivers who fail a roadside number plate test could have their licence revoked, a possible fine or penalty points on your licence if a police officer deems you to be unsafe on the road. 

As 90% of the information a driver uses is visual, roadside screening is important to ensure people aren't putting themselves and other road users at risk. 

In 2012, Cassie McCord, 16, from Colchester, was killed on her way to school by an 87-year-old driver, just three days after he had failed an eyesight test and refused to surrender his licence. Cassie's law allows officers to revoke people's licence and ensure more safety for the public on the roads. 

Chief Inspector Vicky McParland said: "As a responsible driver, it is key you monitor your eye health to ensure there is no impact on your ability to safely drive, both in daylight and darkness, seeking the advice of an optician if you notice any change/deterioration to your sight."