Their Dornier 288 plane tracked the edge of the plume over East Anglia and the North Sea, and towards the Dutch coastline.

BBC: Flight ban 'not over-reacting' say Wiltshire scientists

Models by the National Oceanographic and Atmospheric Administration project that the plume will head over the Pacific for a few days before gradually dissipating into the sea.

FORBES: Tracking Radioactive Drift from Fukushima Nuclear Plant

The plume moved south and east over the 12-hour period of 0600 UTC to 1800 UTC on March 15.

FORBES: Tracking Radioactive Drift from Fukushima Nuclear Plant