Defence secretary Philip Hammond said there was nothing for British authorities to do in the case of the missing British crew of the Cheeki Rafiki yacht lost since last Friday.
"This is in the United States, Canadian air sea rescue area, they are the responsible authority and they have searched it very extensively. The conclusion that they have reached is that there is no hope of rescuing these people now," he said.
The US Coastguard called off its search on Sunday morning for the crew of the yacht which was lost on Friday after it got into difficulties 620 miles (1,000km) east of Cape Cod in Massachusetts.
With no sign of a life raft or of debris, and with nearly 20,000 square miles having been searched, the hunt continues for another day.
Veteran yachtsman Tony Bullimore tells ITV News that there is a "strong possibility" the yachtsmen are still alive in the life raft.