Scientists have found that Royal Navy bomb exercises off the coast of Scotland were the prime cause of a mass stranding of pilot whales which led to 19 dying.
Three 1000lb bombs were detonated underwater by the Navy in 2011 which drove 70 pilot whales onto the beach at the Kyle of Durness in Sutherland.
A report by the Department for Environment Food and Rural Affairs said: "The magnitude, frequency and proximity of the multiple detonations in the day prior to the stranding, and the single high-order detonation shortly after the beginning of the mass stranding, were plausible sources of significant disturbance to any neighbouring marine mammals."
According to The Scotsman, another bomb was exploded after the stranding began.
Despite attempts to herd the whales back to sea, 39 were left stranded by the tide and locals only managed to refloat 20, leaving 19 dead.
Sarah Dolman, of Whale and Dolphin Conservation, told the Daily Record: "Why has it taken four years to publish the report and what measures have the Ministry of Defence put in place to evaluate and minimise the impacts of detonations around Garvie Island, to ensure that it protects whales and dolphins since then?"
The Guardian reports that the MoD says it accepts the report's findings.
A MoD spokesman said: "It identified a number of possible factors that may have influenced events, one of which was the detonation of underwater explosives."