Boaty McBoatface will explore the polar seas as a yellow submarine, ministers have said.
But the new £200 million research ship from which the sub will be launched is to be named after Sir David Attenborough.
Science minister Jo Johnson said a public call for suggestions for the name of the vessel had "captured the imaginations", and the name Boaty would adorn a remote-control sub-sea vehicle instead.
The name RRS Boaty McBoatface topped the poll staged by the Natural Environment Research Council (NERC) with more than 124,000 votes, more than three times its nearest rival.
But the research ship will be named RRS Sir David Attenborough.
The decision to name the new research vessel after the veteran broadcaster, who turns 90 on Sunday, came after the suggestion attracted 10,284 votes in the public vote.
Sir David said: "I am truly honoured by this naming decision and hope that everyone who suggested a name will feel just as inspired to follow the ship's progress as it explores our polar regions.
"I have been privileged to explore the world's deepest oceans alongside amazing teams of researchers, and with this new polar research ship they will be able to go further and discover more than ever before."