Casualties – First World War
No national record of First World War casualties was kept.  You may be able to find information and memorials locally. 

Casualties – Second World War
The Commonwealth War Graves Commission was not responsible for providing graves or memorials for civilians who died as a result of enemy action in the Second World War. However, the Debt of Honour register can be searched for details of the 67,000 Commonwealth civilians who died as a result of enemy action in the Second World War.

Westminster Abbey holds a memorial set of the Civilian Registers.  These can also be looked at in the Imperial War Museum's Department of Printed Books’ Reading Room.  These volumes are arranged by county and borough, and names appear alphabetically.  It is possible to cross refer names, dates and addresses to find the names of all those who died in a single incident.  You can usually find out more by using books such as:

The Blitz: then and now: [3 volumes] edited byWinston G. Ramsey (London: Battle of Britain Prints International, 1987-1990) or local history books.

The Commonwealth War Graves Commission also has records of British children on board the City of Benares torpedoed while being evacuated overseas as well as civilians who died in the internment camps of the Far East.