A body has been recovered from the wreckage of the plane which crashed with Cardiff City footballer Emiliano Sala and pilot David Ibbotson on board.
The Air Accidents Investigation Branch said specialist contractors joined the operation in “challenging conditions”.
It was carried out in “as dignified a way as possible” and the men’s families were kept updated throughout, it said.
The wreckage of the plane, which vanished two weeks ago over the English Channel, had been found off Guernsey.
The Geo Ocean III, the boat carrying the body, arrived at Portland Port in Dorset on Thursday morning.
The Piper Malibu N264DB was en route from France to Cardiff after the 28-year-old Argentine striker made a quick trip back to his former club Nantes two days after his £15m transfer to Cardiff was announced.
Ibbotson, 59, from Crowle, North Lincolnshire, was at the controls when the flight lost contact with air traffic controllers on 21 January.
An official search was called off on 24 January after Guernsey’s harbour master said the chances of survival were “extremely remote”.
But an online appeal started by Sala’s agent raised £324,000 (371,000 euros) for a private search led by marine scientist and oceanographer David Mearns.
Working jointly with the AAIB, his ship, and the Geo Ocean III, began combing a four square mile area of the English Channel, 24 nautical miles north of Guernsey, to make the best use of the available sensors.
Mearns said the plane was identified by sonar before a submersible with cameras was sent underwater to confirm this.