This is a show with Titanic ambition. In a tiny 260-seat theatre, the production attempts to recreate the majesty and the horror of the maiden voyage of the great ocean liner – "at once a poem and a perfection of physical engineering" as the lyrics clunkily inform us – that on April 15 1912 hit an iceberg, and sank with more than 1,500 lives lost.
The story is so familiar that in creating his musical, first seen on Broadway in 1997, (the same year James Cameron's movie was released), Maury Yeston needed to come up with some kind of magic to keep us hooked. And in the first act, to a large extent, he pulls off the impossible. Ably assisted by Peter Stone's strongly structured book, he creates a vivid picture of shipboard life, with each class divided, each character deftly delineated, and tensions beginning to emerge between the managing director of the White Star Line, J Bruce Ismay, Titanic's designer Thomas Anderson and the Captain, who all have different aspirations for the vessel.
On David Woodhead's pocket-sized but brilliantly designed set, director Thom Southerland moves things along with great skill and flair. There are some distinctive numbers: a Gilbert and Sullivan inflected paean to progress from the viewpoint of the first class dinner table; a rousing hymn to hope from the third class passengers dreaming of a better life; a soaring ballad of proposal from a love-lorn stoker. The scene leading up to the disaster, in the song "No Moon", when the high tenor of the lookout rises above the babble of excited voices below, is atmospheric and eerily beautiful.
But then the ship hits the iceberg, with a great crash and a flash of light, and after the interval the show starts sinking too. The problem is it doesn't have anything to add to an already familiar story and its attempts to pluck our heartstrings are scuppered by Yeston's all-purpose, all-encompassing, sub-operatic melodies which can't rise to the heights of emotion required. His lyrics hit the wrong notes too – "if only you could comprehend/I want to be yours till the end" is just one example of moments where bathos replace pathos. And when your major dramatic scene is three men basically shouting "It's your fault" at one another, and looking at blueprints of the fatally flawed ship, your musical is in trouble.
Yet the production continues to grip, with committed and vivid performances, all the more impressive because the cast of 20 take on so many parts. James Gant, so good in Yeston and Southerland's version of Grand Hotel, is excellent again as the first class steward determined to keep up appearances, Niall Sheehy is a heroic stoker and Claire Machin brings vibrant charm to a woman determined to rise above her station in life and have a good time. The band plays on beautifully.
Titanic runs at the Charing Cross Theatre until 6 August.