AFTER this most bizarre week in Westminster, it’s the tarantula that sticks in my mind. I refer to the hairy arachnid kept in a glass box on the desk of the former Tory Chief Whip, now Defence Secretary, Gavin Williamson MP.

Can you imagine a senior manager in any other organisation being allowed to keep a spider on his desk? Junior employees, forced to sit in its presence, would rightly feel intimidated and threatened. Yet this politician, who seems to have the mindset of a Bond villain, is now in charge of Britain’s weapons of mass destruction. Williamson, aka “Spiderman”, was elevated to Defence Secretary in true House Of Cards style following the departure of the incumbent, Michael Fallon, in whose resignation he was almost certainly involved. As Chief Whip, Williamson is responsible for disciplinary action. He would have been consulted by the Prime Minister before she sacked the Defence Secretary for having allowed his hands to stray into no man’s land on a journalist’s anatomy.

A number of Conservative MPs are reported to “have their head in their hands” at Williamson’s appointment. Others have called him names, including one that rhymes with Jeremy Hunt. I can’t recall a senior Tory Cabinet appointment being so openly criticised by Tory MPs who are usually under strict orders to applaud the Prime Minister’s choice to the rafters.

The Spiderman appointment may turn out to be Theresa May’s worst mistake – well, since the last one. Apologists say she is too weak to have mounted a proper reshuffle to replace Michael Fallon, just as she was too weak to defend the politician she used to described as a “safe pair of hands”. So she elevated her crony, Williamson, 41, who has no Cabinet ministerial experience, has never spoken from the dispatch box and is disliked by his colleagues, to one of the highest offices of state. There’s no angle from which this looks good.

And the shuffling surely hasn’t stopped. Having lost Fallon, other ministers could be heading for the exit, including the International Trade Minister Mark Garnier, who has admitted asking his former assistant to buy sex toys and calling her “sugar t**s”, and the Deputy Prime Minister Damian Green, who has been accused of (and denied) inappropriate advances towards a young female journalist.

I’m not saying these ministers have done anything wrong and they deny impropriety, but we live in very strange times when MPs don’t have to be guilty of actual sexual harassment to be accused of it.

There is anyway a dynamic to Government meltdowns. As Alastair Campbell famously put it, when you’ve become the story it’s time to go. Green and Garnier are clearly the story – along with the 36 ministers and MPs on that “sex pest” list circulated by Tory staff in Westminster.

Everyone has been comparing this affair with the Westminster expenses scandal seven years ago. But at least then people were caught doing things that were clearly improper, against the rules and in many cases illegal. MPs did go to jail for expenses fraud, including the former Labour minister Denis MacShane. But none of the MPs on the Tory list is guilty of any obvious crime or misdemeanour. It is mostly gossip about who’s sleeping with who, and even in this increasingly prurient age, sexual intercourse is not a crime.

This makes it incredibly difficult for Theresa May to limit the damage or even know where the damage lies. If she doesn’t dispense with the services of the named ministers, she’ll be accused of condoning improper behaviour. If she does, she’ll be guilty of condemning them without due process. In the meantime, she’s hiding in the bowels of No 10 with a pillow over her head hoping it will all go away.

Enter Ruth Davidson, the Scottish Tory leader, who has no doubts about what to do. She waded into the alleged sex pests in a speech at an awards ceremony in London last week, announcing that the “dam has broken” and that it’s time to use “a pretty large shovel to clean out the stables”. That certainly sounded like a call for the Prime Minister to take action and start clearing away the ordure from her Cabinet and party. And if she doesn’t, I think Davidson knows someone who could.

I’ve been saying all along that Ruth Davidson is not a candidate in the emerging Tory leadership race, and that she couldn’t win it even if she was. Now I’m not so sure. Her intervention last week sounded a lot like positioning, even a job application. The Scottish Tory leader isn’t an MP, let alone a minister in Westminster, and under normal circumstances couldn’t possibly be considered as a UK leadership candidate. But as I say, these are very strange times, when political conventions are being thrown up in the air. Nothing seems impossible any more. And there certainly looks like a vacancy at the top, even though May has said nothing about standing down. After her disastrous coughing conference in October, many people said she was only one crisis away from resignation.

Well, this is one more crisis and May has behaved like a rabbit in the headlights. A Prime Minister must be capable of steadying the ship of state at times like these; must convey authority and possess a necessary streak of ruthlessness.

The “sex pest” problem may have destroyed the leadership ambitions of a number of Ruth Davidson’s potential rivals. Boris Johnson’s prospects of entering No 10 must now be zero, if they ever existed, because of widely-publicised affairs he has had in the past. An entire generation of senior Tory politicians is now looking tainted. Even the Home Secretary, Amber Rudd, who has been suggested as a future leader, appeared on the Westminster list on account of a “workplace relationship” she had with a colleague. Other female MPs and ministers on what has been called the “dirty list” are accused of “fornication”.

Again: they have done absolutely nothing wrong, and the presence of these women on this ridiculous list should not be seen as any guide to their competence. But politics is not in a rational state right now, and in the present febrile climate almost any kind of sexual activity outside marriage seems to be regarded as improper and anything improper a resignation issue.

And yes, Labour is in the grip of much more serious sex allegations, such as that of Bex Bailey, the NEC member who says she was told to shut up about her rape at a party event. But the difference is that Labour is not actually in government right now. Jeremy Corbyn’s team is not handling the most important international negotiations in half a century. The Tory Government is a complete and utter shambles. The Cabinet is falling apart at the very moment that crucial Brexit negotiations have run into the ground in Brussels. No-one seems to be in control and the country is heading for the cliff edge.

It is time to state what is no blindingly obvious: Theresa May must go.