Mark Sheppard really should play Avon in Syfy's Blake's 7 rebootS

Syfy is apparently racing ahead at speed Standard by Six with its remake of Blake's 7, the classic British show about criminals who join a political prisoner to fight an evil space empire. This show will live and die based on the character of Avon, and there's one actor who's uniquely qualified to play him.

Avon, of course, is the sarcastic computer expert who is both an indispensible part of Blake's crew and a huge liability to Blake — likely to betray the rebel leader at any time. In the original BBC version, writers Terry Nation and (more likely) Chris Boucher gave Avon the lion's share of the insanely quotable dialogue, with a sharp barb for absolutely every occasion. And yet, Avon also shows immense vulnerability, and develops one of the all-time great conflicted love stories with Blake, the man he says he wants to be free of.

There could be no worse sin than casting a bland, amiable, vaguely good looking actor as Avon — he needs to be a standout character, who owns the screen every time he's on it. He needs to be charismatic and intense, constantly spouting his nihilistic philosophy about the foolishness of trusting other people — but also thoughtful and filled with a deep remorse.

We mentioned our belief that Mark Sheppard is the best man for the job a while back, but we buried it in a longer piece — so here's our official pitch for the man who played Badger in Firefly, Crowley in Supernatural, and countless other great characters. We can't think of another actor who would bring the level of sardonic wit that Avon requires, let alone all the other stuff the character needs to convey. (Maybe Cumberbatch, but he's busy.)

Sheppard is unmatched when it comes to raw snark and vicious wit, as he's shown every time he gets to say lines written by Ben Edlund on Supernatural. But he's also capable of playing more sympathetic, heroic or antiheroic characters, as he proved on Doctor Who and Warehouse 13. He's got the dark sense of humor down pat, as well as the raw cunning.

And Avon really is going to be the linchpin of any Blake's 7 adaptation — he's the character who stands out right away, as well as the instant fan favorite whose betrayals and little moments of unwilling cameraderie keep the show unpredictable. The casting of Avon is going to be a crucial test for this show — and you really need an actor who's got the proven ability to bring a certain amount of alluring menace to these antihero characters.

So let's hope Syfy gives Mark Sheppard his long-awaited promotion to "leading man" status and casts him as Blake's 7's most fascinating crewmember.