Cam Cameron planned to spend 60 days living on the uninhabitable rock in the Outer Hebrides.
An army veteran trying to set a world record for the number of days living on the tiny North Atlantic isle of Rockall is being rescued by the coastguard.
Cam Cameron set off on 26 May to spend 60 days on the uninhabitable rock, 230 miles (370km) west of North Uist, to raise money for veterans charities.
Above the water level, Rockall is only 100ft (30m) wide and 70ft (21m) long.
Mr Cameron, from Cherhill near Calne in Wiltshire, called for aid after 32 days due to “declining weather conditions”.
The Maritime and Coastguard Agency said it sent a search and rescue helicopter from Stornoway after receiving the distress call at 08.55.
A fixed wing aircraft was also sent to support the rescue.
Before embarking on his record attempt in the Outer Hebrides, the former Gordon Highlander told the BBC he was prepared for the challenge.
Mr Cameron said: “I’ll need to take all water, food, fuel, clothing, safety equipment, everything with me for the 60 days on this tiny little area.
“I’ll have a drysuit with me. I’ve got an emergency position-indicating radio beacon, I’ve got a VHF radio so I’ve got everything I think I need in order to survive.”
However, in a post on Twitter, Mr Cameron’s supporters announced that his challenge was now over.
It stated: “Due to declining weather conditions and sea state at Rockall over the last 24 hrs, Cam has this afternoon declared a mayday.
“An operation to evacuate him from Rockall is currently being coordinated by HM Coastguard. Please do not speculate at this time.”
The current world record for a 45-day stay on Rockall was set by adventurer Nick Hancock in 2014.
He beat the previous record held by three Greenpeace campaigners who lived there for 42 days in 1997, and the former solo record of 40 days set by veteran Tom McClean in 1985.