Abstract
The impact of the Chernobyl incident on the UK is reviewed, with a brief chronology of events and a description of some of the operational problems that arose. The passage of the cloud over the British Isles during 2nd-4th May is described with special emphasis on the elevated deposition of radionuclides caused by rainfall. The use of Derived Emergency Reference Levels during the incident is considered, along with various matters of public concern which surfaced in the aftermath of the incident. Finally some lessons are drawn from this event.