Researchers writing in the Journal of Wildlife Management report there are more deer in the United Kingdom than at any time since the Ice Age and in the absence of natural predators populations are continuing to expand, causing a serious threat to biodiversity as well as causing road traffic accidents and crop damage.
Britain now has a total of six deer species, four of which were introduced since Norman times. The most recent arrival is the Chinese water deer, which became established in the wild in the 1920s.
The deer population is currently estimated around 1.5 million, researchers at the University of East Anglia said.
"Native deer are an important part of our wildlife that add beauty and excitement to the countryside, but left unchecked they threaten our woodland biodiversity," researcher Kristin Waber said.
"Trying to control deer without a robust understanding of their true numbers can be like sleepwalking into disaster. To effectively reduce and stabilize the population, establishing numbers is vital."
A cull may be necessary to keep numbers of deer manageable, researchers said, suggesting that only by killing 50 percent to 60 percent of deer can their numbers be kept under reasonable control.