The world's most expensive Titanic artefact has gone on public display in a centre dedicated to the doomed liner.

The 32ft-long plan of the ship, which was used as a reference guide during the 1912 British inquiry into the sinking, has been passed to Titanic Belfast by a mystery benefactor.

The anonymous collector bought the well-preserved paper diagram at auction for £220,000 last year.

It bears ink marks denoting exactly where engineers giving evidence to the Board of Trade inquiry determined the White Star Line vessel had struck the iceberg on its fateful transatlantic maiden voyage in April 1912.

Expert Una Reilly, who is co-founder of the Belfast Titanic Society, said the plan helped to dispel one of the enduring myths about the sinking.

''There has been for more than 100 years this theory that there was a 300 foot gash in Titanic,'' she said.

''The actual total amount of damage caused by the iceberg was 12 square feet, which is the size of a normal room door. But it was the fact that it was in six different places.''

She added: ''The initial collision with the iceberg caused very little damage but once it was opened to the sea the water just poured in.''

Ms Reilly thanked the mystery benefactor for giving people the opportunity to see the plan.

''It's such a vital part of the Titanic story,'' she said.

The diagram will be on permanent display in one of the centre's nine galleries - the one that focuses on both the British and American inquiries into the sinking.

The £90 million tourist attraction in the old shipyard where the Titanic was built opened earlier this year ahead of the 100th anniversary of the tragedy.

It has so far exceeded visitor predictions, with more than 600,000 people having taken a tour in its first eight months of business.

Judith Owens, deputy chief executive of Titanic Belfast, said there was no better place for the plan to be.

''We are absolutely delighted,'' she said.

''This is one of the most important pieces of Titanic memorabilia and really it feels like for me it has come home.

''It is sitting in our aftermath gallery and it is here for the public to see, which is the most important part of this - it's part of the Titanic history.''