The tank, which is 27m tall standing upright, has no markings and is thought to have fallen from a ship before being washed up on the west of Benbecula.

It was discovered by a dog walker on Poll Na Crann beach - known locally as Stinky Bay - near Griminish.

Stornoway Coastguard is using two numbers on the container to try to find out where the item has come from.

The beach is known as Stinky Bay because of the fermenting seaweed found there.

Alasdair MacEachen, assistant director of environmental services at Comhairle nan Eilean Siar told BBC Scotland: "It's certainly generated a fair bit of interest with people walking on the beach or just travelling along the road, because you can actually see it from the main road along the west side of Benbecula.

Although it looks as if it's empty and it's been ruptured, my advice would be not to go too close to it

Alasdair MacEachen

Comhairle nan Eilean Siar

"It's a big object so you can't miss it, and it's not often you see something like that on the beach.

"It would be standing almost 30m tall and really looks pretty much like a silo. I think it's a bulk storage tank of some sort, possibly for storing some liquids."

Mr MacEachen said they may decide to anchor the container to the beach to stop it from floating out to sea and becoming hazardous to ships, but in the meantime he advised onlookers to keep a safe distance.

"Although it looks as if it's empty and it's been ruptured, my advice would be not to go too close to it," he said. "It's a fairly light construction so you don't want it rolling on top of someone, and with that sort of thing you can never tell.

"My advice would be to just observe it from a distance."