Never-before-seen footage of life aboard the Titanic’s sister ship the Olympic has been restored by historians in Sussex.

The rare film, described by experts as “unprecedented”, was found by builders in a box of film cans marked Cunard in the attic of a house in Ireland.

The reel displays day-to-day life aboard the vessel and gives a firsthand look at luxury cruise liners of the period.

In particular it shows the Olympic travelling from New York to Southampton, featuring unique clips such as the engine room in operation, dancers in the ballroom, people coming down the grand staircase, the cooks in the kitchen and passengers enjoying the liner’s gymnasium.

David Hutchings, historian and author of Haynes’ RMS Titanic Manual and The Titanic Story, described the find as significant. He said: “It’s certainly very rare for footage of this kind to be found, especially the kind that shows the kitchens and the engine rooms in full swing.

“I would say this is significant, it is some of the earliest onboard footage we have of this ship which mostly only exist in still photographs.

“We can date the footage to being made after the end of the First World War when the Olympic had been restored following her war service.”

The Olympic was launched by White Star Line in 1911 and saw service until 1934 – when it was retired and scrapped.

Des Cox, a former sailor turned documentary maker at Snowbow Productions, helped restore the film.

He said: “This is certainly one of the rarest maritime films ever discovered and restored. Just about everyone in the world knows of the Titanic, but this is the very first time you can see just what it was like to have sailed on her.

“The frightening thing is if we hadn’t found the film then I doubt it would have survived and then all these amazing scenes would have been lost forever.”

When it was first discovered back in 2006 it was warped, twisted and stretched. Mr Cox said: “I closed my eyes as the film went through the transfer equipment.

“It came out the other side in so many torn and shredded pieces but thankfully the equipment copied it, so now we have it for the rest of time.”