Titanic (review).Anne Cox joins its maiden voyage to the UK.

But somehow Titanic effortlessly sailed from the big screen onto Broadway and collected a raft of awards.

Now she’s found a safe harbour at the Southwark Playhouse. Titanic lowered the gangplank on Wednesday and swept the opening night audience away with a powerful and compelling musical colossus.

We all cried at Kate and Leo when the “ship of dreams” sank below the waves after striking an iceberg on its maiden voyage. How on earth does director Thom Southerland do the epic justice in a small fringe theatre in trendy Southwark?

Surprisingly easily, as it turns out. The script (and book), by Peter Stone, is heavy on facts and figures- enough to make your head spin-but one thing that sticks is that a vast 900ft liner, the pride of the White Star Line, left for New York, in 1912, with more than 2,000 people aboard.

Titanic has a cast of just 20 tucked into a compact performance space for a chamber production that features a raised deck and little more. Yet our versatile crew, who swap characters throughout, succeed in drawing the audience on board their world of hopes and dreams.

We meet the first class millionaires, led by Astor and Guggenheim, along with their wives and mistresses, and the second class passengers who yearn to rub shoulders with the rich and powerful.

Far below decks are the third class passengers – mainly Irish – who want to escape the poverty of their homeland for streets paved with gold on the other side of the Atlantic.

Shockingly, we’re told, most were locked in on their deck to die, when the ship sank because there were only 20 lifeboats, which were all earmarked for first-class, instead of more than 60 a boat of that size required.

It’s a story whose characters get under your skin. The blossoming romance between the pregnant Kate Mullins (Scarlett Courtney) and Jimmy Farrell (Shane McDaid); the wonderful and enduring love of Macy’s founder Isador Straus (Dudley Rogers) and his wife Ida (Judith Street) who refuse to be parted when tragedy strikes; and the crew, who sacrificed their lives for the safety of the first class ladies (another fact, all 50 bellboys on board, went to their deaths still serving their guests).

The rousing opening and closing songs (In Every Age and Godspeed Titanic)take the roof off. Maury Yeston has done a great job coming up with music (and lyrics) that complement the sweeping grandeur of the story.

No disrespect to “London’s coolest fringe theatre” (which, on opening night, was one of the capital’s hottest, with the audience in dire need of a real iceberg) but this awesome musical really belongs on a bigger, and more mainstream, West End stage.

The dialogue generally is rather hackneyed but, if you’re a Titanic anorak, you’ll not fail to be impressed by some of the statistics that make their way in between the human stories.

The ship’s owner, James Ismay, proudly declares that Titantic is the “largest moving object in the world” and “God, himself, can’t sink this ship!” He’s wrong, of course.

There is no great sinking and not a drop of the great Atlantic in sight but the production is so absorbing that you fail to notice. As the audience leave a roll call of those who died is projected onto the floor. It is a chilling reminder of the souls, including Eaton Bray man Cecil Jackson, who lost their lives.

There are knockout performances from the entire company. Philip Rham as the noble Captain Smith (looking like Capt’n Birdseye with a grand and distinguished beard) is utterly convincing as he takes the helm for his last voyage before retirement.

His second in command, Murdock (a small but memorable cameo from Siôn Lloyd), who blames himself for the disaster; steward Henry Etches keeping everyone’s spirits up right to the end; and the handsome, heroic stokerman,Barrett (James Austen-Murray ) forfeiting his place in a lifeboat.

The dastardly Ismay, is very much the villain of the piece, pushing the new engines harder and harder in a bid to break records, and Simon Green (Phantom) does the character proud. His final act, to save his own skin and flee the sinking ship with the women, is both appalling and shocking.

Book your passage today. Titantic runs until August 31. For tickets and info call the box office 020 7407 0234 or go online www.southwarkplayhouse.co.uk

@LBOanne