A group of ambitious folk with their eyes fixed on the top prize, pretending to be loyal and yet ready to knife colleagues in the back at the first opportunity.

That sums up a big chunk of life at Westminster, which I have reported on up close for more than 30 years. It’s also a pretty good description of the behaviour of competitors in the hit TV series, The Traitors, which is perhaps why I’m so hooked on it.

Of course, presenter Claudia Winkleman’s glossy fringe is the real star. But even setting that aside, the antics of the massed ranks of “faithfuls” as they carry out “banishments” and a secret coterie of “traitors” committing “murders” is non-stop compelling.

For those who haven’t watched it, the Scottish baronial setting makes it akin to a giant on-screen game of Cluedo, but with many more plot twists and possibilities.

The current third series opened on New Year’s Day with first night ratings of over five million and will only build its audience further as the prize pot grows and the number of surviving contestants shrinks.

Currently the designated traitors have the upper hand, with the faithfuls far more likely to turn on one of their own than identify the real snakes in the grass. The way they turned on the amiable – and innocent – Tyler in Thursday night’s episode was especially brutal.

The treacherous ones are adept at covering their tracks with gambits designed to plant seeds of distrust between the others. All the competitors are in it for the money, adding to the prize fund by carrying out daily challenges as a team.

Yet the world of politics is if anything more ruthless still since everyone in it is supposedly there because they believe their own ideas can improve the nation. This means many give themselves permission to behave in startling ways to secure their own elevation “in the national interest”.

Take Michael Gove’s abandoning of Boris Johnson’s abortive Tory leadership campaign of 2016. Gove was supposed to be Johnson’s campaign manager, but at the last moment decided to run himself. In the end both were damaged and fell out of the race. Pure Traitors melodrama.

Theresa May won that contest after keeping a low profile during the EU referendum campaign and hence becoming the only senior figure acceptable to all camps. Several Traitors TV contestants have adopted similar tactics.

I remember back to the John Major versus John Redwood leadership battle of 1995. Michael Portillo was officially supporting Major. But then he was caught having phone lines installed in a putative campaign headquarters of his own and struggled to live that down. Major himself had benefited by chance from an opportune few days out of circulation during the toppling of Margaret Thatcher. Ironically, given that he was about to become PM, he was recovering from a wisdom tooth extraction.

On the Labour side, the biggest shocker was when Ed Miliband stood against his older brother David for the leadership in 2010 and edged him out thanks to having been more matey with trade union officials and backbench MPs in the preceding months. Miliband the elder did not see the challenge coming. Suffice to say fraternal relations became somewhat tense.

Right now Keir Starmer is surely king of Westminster’s phalanx of Traitors. First he promised at the election of 2017, when he was his party’s Brexit spokesman, that Labour would honour the EU referendum result and yet later campaigned to set it aside. Then he stood for the leadership claiming that he regarded Jeremy Corbyn as a friend and would stick to his radical agenda.

A couple of years later he dumped his left-wing pledges and threw Corbyn out of the party. He then won power last year on a moderate manifesto, only to move back to the left with hare-brained policies like paying to give away the Chagos Islands and pushing through huge tax increases. In his own mind no doubt everything he did was in the national interest and therefore perfectly honourable.

Starmer will know that several of those around his Cabinet table have clocked his sinking poll ratings and already have their eyes on his job. The more they profess loyalty to him, the more likely it is that they are burnishing their own personal brands, rather than truly being worried about his.

One major Labour politician with a reputation for being highly principled back in the day was in fact a master at framing ministerial rivals as plotters and backstabbers, with his minions often planting unflattering stories about them.

Maybe he didn’t know the full extent of this brutal spin operation. Or maybe he was deliberately incurious. Because all is fair in love and war, politics and the next thrilling instalment of The Traitors.