The US Navy has found the hull of the missing yacht Cheeki Rafiki - though there is no sign of the four-strong British crew on board the flooded vessel, the US Coast Guard (USCG) said tonight.
A Foreign Office spokesman said the families of experienced captain Andrew Bridge, 22, from Farnham in Surrey, and crew members James Male, 23, from Southampton, Steve Warren, 52, from Bridgwater, Somerset, and Paul Goslin, 56, from West Camel, Somerset, are being kept informed of developments.
USCG said a US navy warship helicopter crew discovered the overturned hull 1,000 miles off Massachusetts.
A close inspection of the debris confirmed the identity of the yacht, which had been flooded.
A coast guard spokesman said: "The swimmer determined the boat's cabin was flooded and windows were shattered, contributing to the complete flooding inside.
"The swimmer also knocked on the hull and reached an arm's length below the waterline with no results. Surface swimmers are not trained divers and do not perform sub-surface operations."
Officials said the coastguard still intended to call off the search as the latest development failed to suggest the crew would still be alive.
It said: "Navy crews observed that the sailing vessel's keel was broken off, causing a breach in the hull.
"The hull sighting has not impacted search planning as teams continue to look for a bright-coloured life raft as their search object.
"The US Coast Guard made an announcement, Thursday, that search operations would be suspended at midnight Friday unless new information or sightings suggested the crew would still be alive. None of the current developments indicate that to be the case."
A Foreign Office spokesman said it was keeping in close contact with their American counterparts, and have informed family members of the missing men of the discovery.
The spokesman said: "The US Navy has informed us it has located the hull of the Cheeki Rafiki.
"We have informed the families and remain in close contact with them and with the USCG who continue to lead the search operation."
The Foreign Office was unable to confirm any details about the possible fate of the crew members.
All four men were on board the yacht when it is thought to have got into trouble around 620 miles east of Cape Cod last Thursday.
Earlier, the Foreign Office said the families "still hold out much hope that their loved ones will be found soon" after US officials said they were preparing to stand down the search operation at 5am tomorrow.
The Foreign Office said: "They were obviously saddened to hear that the US Coast Guard will be suspending the search. But they were prepared for the fact that this would have to happen."
The families met with the Foreign Office earlier today to talk about UK involvement "and any other avenues that can be explored".
"Having spent the week getting to know each other better, along with hearing the endless accounts of survivors, the families are reassured that their men would work as an efficient and cohesive team," the Foreign Office said.
"This gives them additional hope that they will still be found, as the US Coast Guard have found no evidence to the contrary."
US Coast Guard Petty Officer Robert Simpson said a helicopter from the US Navy warship spotted the hull, which had previously been sighted by a commercial vessel last Saturday.
The small boat crew reached the hull and confirmed it bore the name of the 40-ft Cheeki Rafiki.