Six species of deer are living wild in Great Britain:^[1] Scottish red deer, roe deer, fallow deer, sika deer, Reeves's muntjac, and Chinese water deer.^[2] Of those, Scottish red and roe deer are native and have lived in the isles throughout the Holocene. Fallow deer have been reintroduced twice, by the Romans and the Normans, after dying out in the last ice age. The other three are escaped or released alien species. Moose were also formerly native to Britain, before dying out during the mid-Holocene, over 5,000 years ago.^[3] The comparably sized Irish elk, which has the largest antlers of any deer was also formerly native to Britain until becoming extinct in region around 12,000 years ago.^[4]

• Scottish red deer - (subspecies)
• Roe deer

• Fallow deer (was previously native to Britain during the Pleistocene^[5])
• Sika deer
• Reeves's muntjac
• Water deer

• Elk/moose - (on private reserves)
• Reindeer - (on private reserves)

• Irish elk

• 
  Scottish red deer (subspecies)
• 
  Roe deer
• 
  Fallow deer
• 
  Reeves's muntjac
• 
  Sika deer
• 
  Chinese water deer
• 
  Reindeer
• 
  Elk (Moose)
• 
  Irish elk (extinct)