Search teams have retrieved the cockpit voice and flight data recorders from the EgyptAir plane which crashed into the Mediterranean in May, killing all 66 on board.
It is hoped analysis of the black boxes will shed light on why the plane crashed en route from Paris to Alexandria.
At present no militant group has claimed responsibility for bringing down the aircraft.
British foreign secretary Philip Hammond has said British national Richard Osman "must be feared dead" on the information available about crashed EgyptAir flight MS804.
He said: "I can announce sadly there was one British national, a tri-national in fact, British-Australian-Egyptian tri-national on board, Richard Osman, who must be feared dead on the basis of the information that we have at the moment."
Hammond added that he was meeting his Egyptian counterpart shortly to offer assistance.
Work has begun on analysing data from the two black boxes from the fated EgyptAir flight that crashed into the sea in May.
French air accident investigators confirm the signal detected earlier is from a flight recorder.
The head of Egypt's forensics authority said it is 'too early' to know what caused the EgyptAir plane to crash into the Mediterranean sea.