THE number of motorists admitting drinking and driving has almost doubled since 2009.

And Strathclyde region ranks third in the UK for the number of people caught driving while under the influence of alcohol in the last three years, a survey shows.

As many as 20% of drivers also have no idea how many units are in any alcoholic drink, the poll by LV= car insurance found.

A pint of lager is the drink most motorists assume contains less alcohol than it does.

The survey also showed that Greater Manchester is the drink-drive capital of the UK, with more than 3500 caught this year so far.

Of 2028 people questioned, 15% said they had driven over the legal alcohol limit at one point, despite the fact that 88% admitted it affected their ability to drive.

As many as 80% of drivers wrongly guessed how much alcohol lager contained, while most motorists thought a large 250ml glass of wine had two units of alcohol when it actually contains three.

According to a freedom of information request made by LV= to police forces, December is the month in which most drink-drive arrests are made.

After Greater Manchester, the police area in which most motorists have been caught drink-driving this year is Thames Valley (1844 caught), followed by Hampshire (1646), Strathclyde (1600) and Kent (1514).

Over the last three years, the area at the top of the drink-drive table is Greater Manchester (13,056), followed by Hampshire (7006), Strathclyde (6444) and Kent (6319).

LV= car insurance managing director John O'Roarke said: "The only way to be certain of being under the limit is to abstain from alcohol before driving. The key to enjoying the festive season is to plan ahead and don't drive if you've had a drink."