The road safety charity says a survey by Specsavers and RSA Insurance Group shows why government action is needed, with a quarter (25%) of drivers admitting they have not had their eyes tested in more than two years – despite research showing you can lose up to 40% of your vision before noticing the difference.

Many drivers are also failing to respond to warning signs in regards to their vision: one in five (19%) have put off visiting the optician when they noticed a problem. In addition, a shocking one in eight drivers (12%) who know they need glasses or lenses to drive have done so without them in the past year.

Brake, Specsavers and RSA's survey of drivers also found:

More than 1.5 million UK drivers (4%) have never had their eyes tested;

One in eight (12%) have not had their eyes tested for more than five years; and

Of the 54% of UK drivers who believe they don't need glasses or lenses to drive, one third (33%) have not had an eyesight test in over two years.

The only measure currently in place to ensure driver vision satisfies minimum legal standards is the number-plate test carried out from 20 metres away before driving tests, and occasionally at the roadside if police suspect an eyesight problem. This does not test visual field or contrast sensitivity, both of which are important to safe driving, nor is it a totally accurate measure of visual acuity (vision over distance).

It is estimated up to five million UK drivers would fail a number-plate test if they had to take it again.

Julie Townsend, deputy chief executive, Brake, said: ‘Compulsory regular eyesight testing for drivers is a common sense, lifesaving move. If you drive, it's not just your own health you are jeopardising by neglecting your eyesight, but the lives of those around you. That's why it's vital for drivers to get their eyes professionally checked at least every two years – eyesight can deteriorate rapidly without you noticing.’