A new feature-length drama-documentary exploring the sinking of the Titanic will air on National Geographic and Smithsonian Channel next year, marking the centenary of the ship’s sinking.

Nat Geo Channels International and Smithsonian will broadcast Titanic: Case Closed (1×90’) in April 2012, exactly 100 years after the ship sank in the North Atlantic, claiming 1,500 lives.

The news comes as a Titanic double whammy for Nat Geo, which today also announced two specials, Titanic: The Final Word with James Cameron and Save the Titanic with Bob Ballard, as reported by C21.

Bedlam Productions, the UK indie prodco behind Oscar-winning feature film The King’s Speech, has been drafted in to produce Case Closed, along with Airborne TV & Film.

The programme see Titanic authority Tim Maltin travelling across Europe, North America and the Atlantic to uncover the true reasons for the disaster and the nature of the rescue effort. It will include “eye-opening” experiments, “vivid” CGI sequences and dramatic reconstructions, said producers.

Documentary maker Nigel Levy (Horizon, Fatal Attraction) writes and directs. Bedlam’s creative director Simon Breen, who C21 revealed had joined the prodco to lead a push into TV, executive-produces along with Airborne’s Stuart Burrage.

Breen said the show “sheds new light” on the tragedy and added: “The testimonials and evidence gathered truly brings to life an astonishing story and genuinely changes our understanding of a story we thought we knew.”

TV is awash with Titanic-related programming on the eve of the anniversary. The UK’s ITV is prepping Titanic, a four-hour Julian Fellowes-penned drama miniseries, with a host of major broadcasters signed up.

Rival drama Titanic: Blood & Steel (12×60’) is being coproduced by Italy’s De Angelis Group, pubcaster Rai TV, Spanish commercial net Antena 3, 3Arts Entertainment, Artists Studio, Marathon Group, Tandem Communications and Epos Films.

Meanwhile, US net Discovery and France 2 are coproducing Inside the Titanic, another drama-doc, as previously reported by C21.