As many as 123 million working hours are being lost each year due to traffic delays, according to a survey.

Some 11% of people who drive to work are at least 40 minutes late every time they get stuck in jams, found the survey by car insurance provider Churchill.

It is estimated that the UK economy loses at least £752 million a year as a result of the gridlock.

The survey found that, on average, motorists were delayed by 27 minutes at least once a month, which nearly doubled their usual 30-minute journey time. Consequently, those who drove to work were being forced to change their daily routines.

The traditional nine-to-five work pattern is now seemingly a thing of the past, as 51% arrive at work before 8.30am. For 21%, the day in the office starts between 5.15am and 7.30am in an attempt to beat the traffic.

As well as causing early starts, traffic problems result in 12% of employees working longer hours purely to avoid traffic. A further 15% said they have been forced to shift their working hours just to avoid driving on congested roads.

But millions of motorists said they had no choice as, for 30% of workers, there was no feasible alternative form of transport.

Tony Chilcott, head of Churchill Car Insurance, said: "It's incredibly frustrating for motorists to have to adapt their working hours just to avoid congestion on the roads.

"However, many drivers have to accommodate the school run and other commitments in the mornings, so it's simply unrealistic to leave home at the crack of dawn. The result is millions of working hours wasted in traffic jams each year."

The survey was based on responses from 1,095 people who drove to their place of work.