At just past the halfway mark in this six-part series, the stakes were due to be raised in the angels’ mission to bring good to the earth.

With friction between all the characters escalating in this week’s episode – between Tom and Zack, Tom and Mrs. Sheringham, Mrs. Sheringham and Jude – it was only a matter of time before events came to a head; signalled by the inexorable ticking of Mr. Mountjoy’s Doomsday clock.

Of course, there were indications from the beginning that one of the angels was going to slip up and aggravate Mr. Mountjoy – probably Tom as the greener angel of the two, though it could as well have been Zack.

But instead of the slip-up happening as signposted by the script – in the vaguely biblical form of a sexual involvement with a human – the scriptwriters made use of Richard Pembroke’s (Tobias Menzies) diabolical skills of persuasion to trick Tom into messing up.

Until now a somewhat comical figure, despite his menacing presence, Richard’s Luciferan nature has finally come to the fore. There are shades of Paradise Lost here, with a wily Satan playing on his victim’s Promethean (or ill-advised) belief that knowledge – in this instance the knowledge of eternal life – is something that should be shared rather than kept from people.

In a clever twist, Tom is the victim of his angelic side rather than his human side – of the part of him that makes him care about human beings rather than the part of him that wants to be one of them.

Which doesn’t eliminate the possibility that at some point he or Zack will aggravate Mr. Mountjoy further by succumbing to their feelings for the human women in their lives. After this week’s trip-up, the shadow of permanent disgrace (and Armageddon) looms larger than ever over the characters.

Eternal Law isn’t a show that takes a black and white view of human nature. This week’s criminal is shown to be motivated by grief as much as malice. It’s easy to understand why Tom lets himself go astray comforting her.

The script-writers’ willingness to depict human nature in shades of grey makes the outcome of the court cases in the show unusually hard to predict. The angels’ success isn’t measured by whether they win in court but by how effectively they divine and carry out Mr. Mountjoy’s will.

One of the unlauded stars of Eternal Law is the city of York. The aerial views of breezy spires, hills and grey stone make it look like something out of a hymn – the perfect backdrop for a story about the battle between good and evil.

Aired at 9pm on Thursday 26th January 2012 on ITV1.

> Buy the Series 1 DVD on Amazon.

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