A rare, dark glimpse of the days that followed the sinking of the Titanic is being sold off by an English auction house later this month.

Henry Aldridge and Son is selling a photograph of a burial at sea, believed to be on board the Mackay-Bennett. The cable ship based out of Halifax was the first to search for bodies after the Titanic sank on April 15, 1912.

“It’s pretty much an unwritten rule that no one went on the Mackay-Bennett with a camera for obvious reasons,” said Andrew Aldridge, of the auction house.

“In the grand scheme of things, it’s a very valuable photograph. We’re estimating £3,000 [$5,000] to  £5,000 [$8,350], which for a photograph is a lot of money. However, it is an incredibly rare image.”

Aldridge said the photographer likely had to be discreet, which would have been difficult considering the size of cameras at the time.

“It shows us the horrific conditions aboard that ship. You had people being buried at sea. You look at that image, and you can see the bodies are stacked between two and three high.”

Aldridge said another remarkable feature of the photograph is that historians are certain they can pinpoint the day it was taken.

“In the foreground, there is a body with a small canvas bag attached to it with the number 177 stencilled on it. That was to a gentleman called William Mayo, and we know William Mayo was buried at sea on the 24th of April, 1912," he said.

The photograph will be sold during a sale that includes 250 pieces of Titanic memorabilia on Oct.19.

The Titanic went down after hitting an iceberg 565 kilometres south of Newfoundland, killing 1,517 people.