Forget Netflix – this deliciously devious iPlayer reality show is the ultimate festive binge watch

The last episode of The Traitors is on tonight – boooo! – and then where will the series be? Behind you! Thankfully, Auntie Beeb's prezzie sack includes having the entire series on iPlayer, ready for you to binge-watch, open-mouthed. Think you'll be able to guess the winner? Oh no you won't! 

I'm using some panto clichés there because, firstly it's Christmas, and why not? Secondly, The Traitors – the BBC's backstabbing and deceit-based game show – features pantomime villains, a cast of loveable idiots, a preposterous castle setting and the ultimate dame in the form of Claudia Winkleman. She rocks a succession of absolutely ballistic outfits during the course of the series, and gives every impression that she has no idea what's going on. And she's the host! You'd be able to see the fear in her eyes, if they weren't permanently hidden by the perfect fringe of her luxurious mane of hair.

What follows does unavoidably contain some very mild spoilers, so you can just click on this link if you like…

• Stream all episodes of The Traitors on iPlayer

What is The Traitors about?

Have you ever played the party game Mafia? Well, it's basically that. 22 players take part, three of whom are 'Traitors', and 19 of whom are deluded sorry, I meant 'Faithfuls'. Or, as most of them usually put it, "100% Faithful, I swear on me mum's eyes, I am!" 

The rules are actually pretty simple. The contestants spend each day together in and around a Disney-style castle in Scotland – it usually serves as a lavish wedding venue, you won't be surprised to learn. Each day there is some sort of task where the contestants can win money to add to a prize fund that the eventual winner or winners will walk away with. Mainly the tasks are not all that memorable, although there is a good one that involves walking blindfolded across a precarious rope bridge. It's okay; they're on safety ropes.

The real meat of the show, however, is the contestants interacting. During the course of each day, they talk to their teammates for the task, and to everyone else when chillaxing back at the fairy-tale chateau. Obviously, the Traitors are trying to convince everyone they are Faithfuls, while the Faithfuls are trying to unmask the Traitors. Groups form, allegiances are made, backs are gently stabbed.

At the end of the day, they all gather around a round table, accusations fly and eventually someone is voted off or 'banished'. Once banished, they have to stand up and reveal if they are a Traitor – cue shock and hurt feelings from the betrayed – or a Faithful – cue remorse and increased paranoia from the remaining players.

The remaining Traitors can then choose to 'murder' another Faithful overnight. Those left alive only find out who's gone when they arrive for breakfast the following morning. 

And that's it. 

Well except that's not it, because some twist to these rules is announced by Winkleman in practically every episode, to the point where it starts to feel like she's making it up as she goes along. But those are the core rules, in all their seeming simplicity.

Why is The Traitors so good?

You hear a lot of Traitors fans saying things like, "I normally hate reality shows but I can't get enough of this one." That's certainly true for me – I am a Faithful to The Traitors, 100% mate! I swear on everything! 

The reason is simple: the format is ingenious and the contestants are great. Bless them, they try so hard. Probably the making of the series is that it takes them absolutely AGES to pick the first of the three traitors, and when they do it's because one of the other Traitors, erm, betrays them. 

In every other episode, the Faithful are absolutely certain they have picked a wrong 'un, only to discover they've booted out a fellow Faithful. You will be screaming at the telly as you listen to the crazed logic they use to pick someone to banish each week. The lines between it being a game and it being real start to blur and warp. 

What makes it so painfully funny and such a great watch, is that aside from The Traitors – Wilf in particular – most of these people are terrible at playing this game. They start picking people to banish because they don't like them, but of course, the entire point is that The Traitors are going out of their way to be likeable, so nobody will suspect them. They then subtly drop little hints about innocent Faithfuls, and before you know it the rest of the group turns on some completely blameless person and banishes their ass. There is so much groupthink in this series.

So the Faithful mob, high on adrenaline, paranoia and free booze, kick out someone hapless. The Traitors then murder someone relatively clever who could be a threat. 

As the series wears on, some of the remaining Faithful start to wonder about this. "I can't understand how I'm still in the show," they say. Of course, the truth is, it's largely because the Traitors consider them too clueless or easily led to be a threat!

All of this could become painful to watch, but the contestants seem like a very genuine bunch of people. Even the Traitors – who by definition are not genuine at all. Many of the Faithfuls are almost painfully earnest, which makes their serial banishment of clearly incorrect suspects simultaneously sad and yet hilarious. 

When a Traitor is banished, it's more by luck than judgement, with contestants openly saying, "I don't think I'm right here, but I've tried everyone else." Their final unmasking as devious, manipulating bastards causes genuine shock and soul searching, as well it might. 

Not all of the contestants are very clever, but none of them are outright dumb. Okay, maybe Aaron. But the show doesn't hold them up to mockery, and if the players were all geniuses or Machiavellian schemers, it simply wouldn't work. They seem to really like each other as well, which immediately makes this a different proposition to practically every other reality show ever. Sure, some of them are more annoying than others, but nobody is toxic. Even The Traitors are sufficiently likeable that you begin to fear they may be sociopathic murderers or con artists in real life. Hopefully not, though.

The paradox of a bunch of people who enjoy each other's company, yet are ultimately all out to get each other, makes The Traitors a total winner. The stakes aren't even all that high. The most that any winner of the show can make is £120,000 – and that's only if the teams ace every single daily task. Moreover, if more than one Faithful or Traitor is left at the denouement, the fund will have to be shared. Players keep saying the prize money is, "life-changing." It's really not, but I must say it's great that the prize motivates them so highly – the money, and the thrill of the chase.

If you haven't seen The Traitors yet, I envy you – it's all there to enjoy in one glorious binge, totally free, on iPlayer. Unlike those of us who watched it as it was broadcast, you'll never have to count the days to the next twist, the next stupid decision and the next murder most foul. Consider your Christmas entertainment sorted.

• Stream all episodes of The Traitors on iPlayer
• The final episode of The Traitors is on tonight, Thursday December 22, at 9pm