Motorists driving through forested stretches of East Anglia – particularly around Breckland – have been warned to slow down and stay alert to avoid a potentially-fatal crash with a deer.

Highways England, the Deer Initiative and the Country Land and Business Association (CLA) have issued the warning with the autumn rutting season in full swing, increasing the dangers caused by deer wandering on to rural roads.

This period of heightened activity between October and December sees bucks become more territorial and aggressive, and young deer dispersing from their breeding areas.

About 1.5m deer live wild in the UK, and collisions between vehicles and deer are estimated to cause as many as 20 deaths every year, with 700 human injury accidents, and 74,000 of the animals killed.

The eastern region is particularly prone to these accidents, with the Deer Initiative naming the B1106, A1066, A134, B1107, A1065 and A11 roads in and around Thetford Forest as some of the nation's biggest deer accident hotspots.

CLA East regional surveyor Tim Woodward said: 'You really need to expect the unexpected when driving through woodland areas at this time of the year. Very often, deer can appear as if from nowhere and can either freeze in your headlights or panic and run across both lanes of traffic.

'With this in mind, it is vital to look for signs warning of the dangers of deer on the road and slow down accordingly. These can be large animals and hitting them at speed will not only put your life in danger, but the lives of your passengers and other road users.'

A spokesman for Norfolk police advised if an animal has been injured, or if the driver felt there was a need for police involvement, they should find a safe place to stop and report the incident by calling 101. The police can contact a network of deer wardens who can help the animal.

Highways England's advice to drivers:

• Check your speed and stay alert when you see deer warning signs or are travelling through a heavily wooded stretch of road.

• If your headlights are on, use full-beams when you can, but dip them if you see deer, as they may 'freeze'.

• More deer may follow the first one you see.

• Try not to suddenly swerve to avoid a deer. Hitting oncoming traffic or another obstacle could be even worse.

• If you have to stop, use your hazard warning lights.

• Do not approach an injured deer – it could be dangerous.

To report a deer-vehicle collision, or for more safety advice, see www.deeraware.com.