Perfect rainy Saturday afternoon entertainment, even if you happen to be watching it in the middle of the week, BBC One’s Merlin returns with the final half of the second series.

While it’s true that, for the most part, Merlin follows that old genre rule of ensuring that the supporting cast is significantly more compelling than the main character (step forward Anthony Head and Richard Wilson, both doing interesting things with roles than could just as easily be simply phoned in), Colin Morgan makes the title role engaging and attractive, despite the inconsistencies with the larger myth (really, this boy will grow up to be the wisest and most powerful wizard of all time?).

The plots (many of which have to do with Merlin hiding his magic or the dragon downstairs revealing his true motives) are direct and simple – sometimes too simple. There doesn’t always seem to be a great deal to do if you’re not a male character: in one scene, Morgana (Katie McGrath) has an entire conversation where she’s required only to shake or nod her head. It’s not as if her character couldn’t find a voice, it just seems that the writers couldn’t find anything for her to say.

But these are minor quibbles, because this is all rather pleasingly old-fashioned: there’s a lot less swords and spells, and a lot more darkly muttered conversations in torch flickering tunnels. This could mean that the smallest members of your household might get a bit fidgety, but anyone who’s ten and above will respond to the intelligent-sounding plots and anyone even older will have fond memories of the likes of Dick Turpin and Catweazle (both due returns, surely?).

While it’s a bit of a stretch to buy that this callow youth will one day guide England into greatness, and equally a difficult ask to believe that Merlin will knock Doctor Who aside in our affections, this is nicely paced, occasionally thrilling, “Robin Hood: The Smallville Years”-style entertainment.

Released on DVD on Monday 8th February 2010 by 2Entertain.