Ever since Hugh Laurie nipped across the pond to play House, a string of other leading British actors have put on their water wings in pursuit. America, it seems, just can't get enough of us Brits at the moment. But, like most Americans, they usually want to have their (very large) cake and eat it, exploiting our reserved professionalism then asking: "Now play it again ... as a New Yorker." What makes Lie To Me so good is the fact that Tim Roth is the same rough-edged Englishman we expect. His curmudgeonly ways and sarcasm jar with that sickly sweet gloss of American drama, making us feel altogether more at home.

Over half way into the series and Lie To Me is really starting to come into its own. The overt close-ups on facial 'micro-expressions' - which Cal Lightman (Roth) and his colleagues are hired to spot to weed out liars - are no longer needed now viewers are up to speed, so the whole thing is altogether more subtle giving greater freedom to concentrate on the characters.

There have been the usual hints over the last few weeks of a dark secret that drives Lightman, and last night we finally learnt that he blames himself for not picking up on his mother's unhappiness before she killed herself. (Although I could have told you that much from watching the trailer, which kind of ruined the big reveal near the end - why do channels have to do that?)

The suicides of three young Indian girls in similar circumstances proves too close to home for Lightman, who becomes obsessed with discovering what drove them to it. Foster, too, is struggling to cope with her emotions as she remains in denial over her marital difficulties - apparently forgetting that Lightman and his gang are ninjas in spotting liars and know it's patently obvious her husband is hiding something.

Even the unfeasibly cheery Loker is given something to rail against this episode, as he investigates a Madoff-style investment scam with Foster. Having discovered a terminally ill Wall Street banker is actually taking the flak for his daughter, Foster agrees to keep this from the authorities providing the victims get their money back. But it seems Loker would rather see pensioners die in a hovel than let "devil spawn" like that get away with it, so goes behind Foster's back to report it. This one is bound to run and run throughout the rest of series, as Loker confesses to Torres and brings her into his professional betrayal.

The fact the show isn't confined to being merely a police or medical procedural gives it far more scope than you'd think for something based around body language. Add to that neat little touches like using video of real instances where public figures have been proved to have lied (take a bow, Bill Clinton - who has featured in almost every episode so far) and Lie To Me is a refreshing change from the likes of CSI and co. Whether it has the legs to go more than one series is debatable, but for now I'm happy just to enjoy this one.