<i>Titanic</i>.

Titanic.

Channel Seven, Wednesday, 8.30pm

You'd think after That Movie there'd be nothing left to say about this most famous shipwreck, but Julian Fellowes (Downton Abbey) has given it a red-hot go. And from the oboe on the soundtrack to the host of familiar character actors, it's obvious we are seeing something different: not Hollywood, but classic British period drama. It's also obvious that with Titanic, Fellowes is continuing to pursue his obsession with the British class system, and this is a perfect vehicle for it.

The ship epitomises that system with its clear physical demarcations between working, middle and upper classes. Certainly, with its broad sweep - from the workers in the boiler rooms through the worthy second-class passengers to the uptight toffs on the upper decks - there's plenty that will be familiar to, and appeal to, Downton's hordes of fans. It also makes it great material for a big, meaty mini-series with plenty of layers and textures.

In this opening episode (the first of four), we meet a range of folk from various stations in life and of various levels of likeability, with Linus Roache as Hugh, Earl of Manton, anchoring the ensemble with that mix of stiff upper lip, entitlement and noblesse oblige Fellowes so convincingly creates. Issues of class are further enlivened by the presence of several (gasp) Americans in among the nobles, all with very un-British manners and all with broad and not entirely convincing American accents. Indeed, alongside some excellent performances there is certainly quite a bit of Big Acting here, but in such a big story - on such a very big ship - it's easy not to mind.

There's also a generous quotient of matchmaking and romance and plenty of familial drama, both above stairs and below. In fact, we get so caught up in the characters it's easy to forget that the whole adventure is about to come to grief. If anything's lacking, it's that very sense of foreboding, but perhaps that's deliberate. An integral part of the Titanic mythos is everyone's absolute faith in its unsinkability and - especially here - in the upper-class belief in its own invincibility. And don't worry. If you get to the end of this ep and imagine we're going to spend the next three floating in the Atlantic in lifeboats, we are not. I don't think it is a spoiler to say that from here flashbacks are used to reintroduce incidental characters in this ep, give us their stories and provide a range of different perspectives from different times in the ship's voyage. The result is big, rich and very satisfying.