EVERY driver involved in an accident in Oxfordshire this month will be asked to take a breath test.

Extra patrols will also be carried out across the county at all times of day.

The crack-down is part of Thames Valley Police's annual Christmas anti-drink-driving campaign, Operation Holly.

In particular, the force has warned people to think very carefully about the morning after.

After just four pints of lager, the average adult may not be safe to drive for up to 13 hours.

That means if you finished drinking at 11pm and went home, you could still be over the limit at midday the next day.

Online calculators to work out when you might be safe to drive - LIKE THIS ONE - allow one hour for each unit of alcohol, plus an additional hour for the first drink to allow for the alcohol to enter the bloodstream.

It then rounds up the calculation to the nearest half hour.

The calculator bases its calculation from the time you stop, not when you start drinking. 

Police have also warned all drivers that there will also be drug testing, and that just a trace amount in a person's system could lose them their licence.

Thames Valley Police has also called on good citizens to 'shop' careless road users who they suspect might be over the limit or on drugs.

If you know someone who drink or drug drives you can report them to on 101, by text 077814 80999 or call 999 if they are driving or immediately about to drive under the influence.