It happened so fast. Villain Richard (Tobias Menzies) went from being the urbane, snide but ultimately ineffectual foil to Zack and Tom that he’s been for the past five episodes to a Luciferan menace capable of duplicating himself and taking on another man’s form.

If we’d known about his powers a bit earlier in the show it might have bolstered the occasionally flagging suspense. He could have been scary as well as funny.

The vagueness that has made Eternal Law hard work to follow at times cropped up again in this final episode. Richard seemed to be trying to tempt not just Zack (Samuel West) but Mrs. Sheringham (Orla Brady) too – who has presumably already fallen by loving a human being and becoming human herself, though it’s never called that and inexplicably doesn’t seem to matter as much as the possibility of Zack falling.

If he got her to go off with the late husband’s brother and leave the boys then that would be bad – understandably, perhaps, but surely not enough to make Mr. Mountjoy wash his hands of the world.

Then there was the odd scene in which Richard and Zack wrestled in the cathedral. It should have and could have been amazing – both thematically and visually – but instead it jarred beside their previous more low-key interactions.

At this final stage in the drama, ‘much ado about nothing’ is the phrase that comes to mind about the angels’ mission on earth, Richard’s attempts to undermine them in the eyes of Mr. Mountjoy and, above all, Mr. Mountjoy’s obsession with his angels’ celibacy.

It’s a measure of the quality of the acting that we care as much as we do about the downbeat ending. Zack’s fall is genuinely disappointing – not because he gave in to his feelings but because he (and everyone else) probably won’t be spared. Which seems a shame because he and Hannah (Hattie Morahan) had a nice chemistry going. Perhaps the real villain of the piece is Mr. Mountjoy himself.

The courtroom scene in this episode was sizzling with Zack – performing as barristers must but for higher stakes than theatre actors perform, falters, flops and fails in court – irritating the judge and nearly giving the man he’s defending a heart-attack, only to make a surging come-back just when it was getting almost too painful to watch.

Eternal Law wraps up with a sense of never really having got started: six episodes of great acting, witty dialogue, a beautiful setting and a strong concept marred by lack of development.

Aired at 9pm on Thursday 9th February 2012 on ITV1.

> Buy the Series 1 DVD on Amazon.

What did you think of the episode? Do you hope Eternal Law returns for a second series? Let us know below…