Motorists are being warned that with the clocks going back tomorrow, the risk of colliding with deer increases, costing millions of pounds.

Scottish Natural Heritage (SNH) issued the seasonal warning that car accidents involving deer peak at this time of year, with night falling earlier. The busiest commuting time also coincides with deer coming out to feed on grass verges.

According to SNH, the most recent deer-vehicle collisions research indicates there are more than 7000 deer-related motor vehicle accidents every year in Scotland, on average causing about 70 human injuries. The economic value of these accidents is near £5 million.

Many assume that most incidents with deer occur on more remote Highland roads, but in fact up to 70% are on trunk roads or motorways. In addition, when traffic volume is taken into consideration, the risk of a collision with a deer is about twice as high per vehicle-mile driven in Scotland compared to England, according to the Deer Vehicle Collisions Project.

Sinclair Coghill, SNH deer management officer, said: "From October to December, there is a higher risk of deer on the road as deer move down to lower lying ground for forage and shelter, with the highest risk from sunset to midnight and shortly before and after sunrise.

"If you do hit a deer, report it to the police, as the deer may be fatally injured and suffering."

Other tips include: SNH, in conjunction with Transport Scotland and Traffic Scotland, are placing warning messages on electronic variable messaging signs.

From Monday next week until November 18 the signs will warn motorists at key locations on: the A9 from Falkirk to Inverness, Wick and Thurso; the A87 from Invergarry to Skye; the A82 from Glasgow to Fort William and Inverness; and the A835 from the Black Isle to Ullapool and into Sutherland.