The UK's largest electricity producer and nuclear operator is yet to decide how to replace Gibson, who has left without a new role lined up.
Gibson joined British Energy as head of comms four years ago (PRWeek, 18 October 2003), reporting to director of corporate affairs Robert Armour.
A well-known figure in corporate comms, Gibson was previously director of regulatory affairs at Energis. Before that, he was public affairs director at consultancy Grant Butler Coomber.
British Energy head of media relations Sue Fletcher will take over Gibson's responsibilities on an interim basis. Fletcher said that the electricity producer had not yet decided how to replace Gibson. She added that he was currently in Australia and was still considering his next move.
In 2004, the Government's investment of more than £3bn in British Energy was approved by the EC and the company was reclassified as a public body.
Meanwhile, the fate of two British Energy reactors could be sealed by the end of the month when the Nuclear Installations Inspectorate publishes a review into Hinkley Point B in Somerset and Hunterston B in Scotland.