An investigation into the performance of lifejackets worn by three fishermen who died after their boat sank has been widened out to other parts of Europe.
The men lost their lives after abandoning the crab boat Louisa off Mingulay last year.
The coastguard and maritime accident investigators have been examining the lifejackets and how they are tested.
Partners agencies elsewhere in Europe have been contacted about a wider research and testing programme.
The survival aids involved in the Louisa incident are understood to be widely used.
Skipper Paul Alliston, 42, from Lewis, and crewmen Chris Morrison, 27, from Harris, and Martin Johnstone, 29, from Halkirk, Caithness, lost their lives after abandoning the boat.
A third crew member survived by swimming to rocks.
Following an investigation of the sinking, the Maritime Accident Investigation Branch (MAIB) reported last month that the three men who died had been unconscious.
However, the lifejackets they were wearing did not turn the men onto their backs and keep their airways clear of the water as the aids would have been expected to, according to the MAIB.
The MAIB recommended an urgent review by the Maritime and Coastguard Agency (MCA) of the jackets and how they are tested.
On the latest developments, the MCA said: "This is the first time we have had a concern identified with an in-service lifejacket and we are investigating urgently.
"We have already carried out a series of targeted tests at two test facilities as part of a package of work to substantiate the concerns with this type of lifejacket and are now in discussion with our European partners about a wider research and testing programme.
"It is our intention to work with our international partners to better understand the issue and to develop a proportionate response to any problems identified."