Adventurer Nick Hancock in bid to spend night on Rockall
An adventurer was due to make an attempt to get himself onto the remote North Atlantic islet of Rockall where he plans to stay the night.
The volcanic rock is 30m (100ft) wide and 21m (70ft) high and a 250-mile (402km) boat trip from Stornoway on the Western Isles.
Nick Hancock was hoping to reach Rockall by early Friday morning.
His attempt aims to raise money for the charity Help for Heroes, which supports injured military personnel.
Last year, Belgian radio enthusiasts succeeded in their attempt to broadcast from Rockall.
The Rockall 2011 group had been trying to get onto the rock for almost a week but were initially defeated by high winds and huge seas.
Two eventually made it onto Rockall and transmitted overnight using amateur radio equipment.
The expedition was part of a programme called Islands On The Air (Iota) where radio hams try to log contacts with remote locations.
The UK annexed Rockall in 1955, but its ownership is disputed.
In the past Ireland, Iceland and Denmark have lain claim to the rock and to the possible oil and gas reserves surrounding it.
The earliest recorded landing on Rockall was believed to be in 1810, by an officer called Basil Hall from the HMS Endymion.
Mr Hanock's venture will be told in Rock on Rockall on BBC Radio Scotland on Monday at 16:00.