Alyson Hannigan

Yes, it’s a cosy US sitcom with a cacophonous laugh track. Yes, it’s about unfeasibly jolly New Yorkers living in unfeasibly nice apartments. Yes, it’s obviously been conceived as a replacement for Friends. And having purchased the rights, BBC2 lost its nerve and buried it in obscure Sunday-night slots.

But How I Met Your Mother became a sleeper hit last year in the States, where it’s just returned for series two. Quite right: it’s a little bundle of joy.

Just like Friends, it concerns a group of 20-something pals who have formed an "urban family". Lovable lunk Marshall (Jason Segel) and his nice-as-apple-pie fiancée Lily (Alyson Hannigan) have the sort of perfect relationship that their friend Ted (Josh Radnor) craves. So we follow Ted as he dates half of New York in search of his kids’ future mom, making that fateful step from single gadabout to settled adult.

Lifelong pals struggling through universal rites of passage was the pitch for Friends, but it got lost somewhere among the sharp one-liners and million-dollar salaries. HIMYM holds onto that warm feeling. The show’s hook - each episode starts with Ted in 2030, telling stories to his kids about 2005 - adds to the feeling of nostalgia for precious days gone by.

And while it comes with a small spoonful of saccharine, Ted’s quest for that elusive perfect romance is genuinely affecting. As co-creator Carter Bays, on whom Ted is based, puts it: "How do you go about searching for what’s essentially divine intervention?"

No need to have a sick-bucket handy, though. Brutally puncturing the schmaltz is Neil Patrick Harris’s storming turn as Barney, Ted’s other friend, who thinks a steady relationship is slightly less appealing than death. He’s an almost sociopathic woman-chaser who, although we never actually see him succeed, does nothing but advise Ted on how to be a sleek, ruthless lothario. Like Seinfeld’s Cosmo Kramer, Barney’s the crazy guy who has all the best gags ("You can’t take a date to a wedding! That’s like taking a deer carcass to a hunt!").

Harris is best known as Doogie Howser MD, the punchably precocious teen surgeon from the early-90s show of the same name. Now, as he nails line after line, you can see the flint-eyed determination of a man who knows this is his last chance to avoid people shouting "Hey, Doogie!" at him in the street for eternity.

Throw in some cute observations and neat storylines (the girl who suggests to Ted that they only have one perfect date, during which they don’t kiss or even exchange names; the drunken night that Ted has to piece together the next day via a series of interviews) and you’ve got a great example of the archetypal mainstream US sitcom. It does nothing we’ve not seen before, but it consistently does it well. Before you know it, 25 minutes have glided past and you’re in a sunnier mood than you were before.