Easily the best episode of the series so far, The Wicked Day sees an elaborate feast being held in honour of Prince Arthur’s birthday by the people of Camelot. However, some of the performers harbour a special gift for Arthur that probably wasn’t at the top of his wish list; assassination.

Such a done-to-death setup may not sound like a candidate for such a glowing review, but this represents a mere fraction of what goes on in the episode. However, for reasons we’re sure you’ll appreciate come Saturday, you won’t want a moment of it spoiled for you.

Suffice it to say that The Wicked Day is Merlin at its best, synthesising comedy and tragedy incredibly effectively. This is most evident in the ever-reliable performances given by the two male leads, who simultaneously produce their funniest and most emotionally truthful performances in the show’s entire four year run. The other principal cast member involved in the main story delivers an absolutely exquisite performance that’s sure to move a sizable proportion of the audience to tears.

The episode’s greatest success is the surprisingly simple emotional story at its core, which feels earned and genuine.

We’re not without our niggles. After his valiant and noble sacrifice in last week’s episode, it seems strange that everyone in Camelot appears to have completely forgotten about Lancelot already (maybe even the characters don’t believe that he’s gone for good).

Speaking of the previous episode, the assassins involved in the earlier sequences here have obviously been taking tips from Morgana, judging by their technique, foregoing the most obvious way to kill the prince in favour of a much more difficult and ultimately doomed strategy instead. They’re such a tiny part of the story though that the momentary lapse in the audience’s willing suspension of disbelief caused by this logical inconsistency really shouldn’t hinder viewer enjoyment very much at all.

It also seems a shame that the brilliantly nuanced character of Morgana appears to have been reduced to a cackling villainess, although astute fans will still have some sympathy for Morgana, a woman who was poisoned by the only person she trusted enough to confide in. More than any TV villain in recent memory, Morgana has a genuine, credible motive for hating the central characters; we’d just love the show explore that a little more.

But leaving aside pedantism, The Wicked Day really is a phenomenal achievement. This is an episode you can’t miss.

Airs at 8.15pm on Saturday 15th October 2011 on BBC One.

> Order the Series 4 Volume 1 DVD on Amazon.

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