A milk flask now represents the final few moments between a heroic husband and his wife as they attempted to flee the sinking Titanic liner in 1912.

It forms part of an untold tragedy which has only just emerged after a collection of artifacts and letters came to light almost a century after the disaster.

Shop worker Arthur West, then 36, thrust the flask into his wife Ada West's hands as the rescue boat she and the couple's two children were aboard was lowered into the ocean.

Newly widowed, Ada, then 33, described her husband's bravery in numerous letters she wrote to relatives and in the account she gave to investigators following the accident.

After the disaster Ada and her girls returned to Britain but barely spoke about the nightmare to people outside of their family.

The family archive -- including the flask and letters -- was handed to Barbara, the youngest of the couple's children who, until her death in 2007, was the second to last British survivor of the legendary liner.

The collection, which has finally come to light 97 years on and is now being sold by family members, is expected to fetch around $87,460 at auction.