To investigate the smoke cloud the Facility for Airborne Atmospheric Measurements, a research aircraft operated jointly by NERC and the Met Office, made two flights on 12 and 13 December. In the first flight the edge of the plume was followed along the south coast of England. Carbon monoxide, nitrogen oxides and ozone concentrations were found to be low with soot particles being the major component in the cloud. The second flight went into the centre of the plume to obtain data to help forecasting and emergency teams.