MPs have called for action as more than half of Britons – 54% – admitted to driving while too tired, and one in six said they had fallen asleep behind the wheel.

The survey of 4,000, from OnePoll, showed that of those who had dozed off on the road, 69% were overweight, a major cause of obstructive sleep apnoea (OSA) – a common disorder.

As many as 700,000 people in the UK could suffer from sleep apnoea, which disrupts sleep and causes acute tiredness. It is treatable, yet many drivers seem to be ignorant of what it is, and how to spot the symptoms, it is claimed.

At a Parliamentary reception, road safety charity Brake called for a campaign to alert all drivers to the importance of adequate sleep, and the need for an immediate visit to the GP if OSA is suspected. An estimated 265 deaths are caused each year by tired drivers – that’s five every week – but that could be just the tip of the iceberg.

MPs from all major parties – including Norman Lamb (Liberal Democrats and political advisor to Deputy Prime Minister Nick Clegg), Peter Bottomley (Conservative) and Meg Munn (Labour) – backed the awareness drive.

Professor Anthony Leeds, of Cambridge Weight Plan, said sleep apnoea caused snoring, interrupted by pauses in breathing, and choking and gasping during sleep – and obesity was a big risk factor with professional drivers likely to be the worst affected.

He said: “And yet a solution is available – recent evidence in the British Medical Journal showed effective weight reduction could improve a high proportion of those affected by severe or moderate sleep apnoea (26 out of 30) in a relatively short time.”

Julie Townsend, deputy chief executive of Brake, said: “It is horrifying to think that so many people who drive for work may be vulnerable to sleep apnoea. We need policy-makers to work with companies to ensure employees are not putting themselves and others in danger. But drivers themselves must also take responsibility. Getting behind the wheel when you haven’t had sufficient sleep can be deadly.”

Anyone with the following tell-tale signs of sleep apnoea should see their doctor, says Brake:

• Daytime sleepiness with episodes of falling asleep while driving or operating machinery
• Choking or gasping during sleep and/or loud snoring
• Frequent awakenings to restart breathing during the night
• Frequent silences during sleep (due to stopping breathing) reported by a partner.