Did you get fat over Christmas? The latest 1990s disease is FAT - Festive Auto Tension. Family feuds can erupt when people get into their cars, which could lead to irritability, volatile disagreements and serious arguments between drivers and passengers, according to the RAC.

The motoring organisation said:

Spending too much time with relatives could be stressful - yet 83 per cent of the population spent Christmas with their families;

Too much food could affect driver alertness;

Two thirds of drivers rowed with passengers, while 72 per cent admitted their driving suffered when they were arguing;

The most common cause of in-car rows was poor map reading and getting lost.

"Arguments outside the car at Christmas eventually boil over in the confined space of the car and cause distress on the road," said RAC psychologist Conrad King. "Going for a long walk or exercising is often the best way to beat the festive tensions. So now ya know.