So what do former Prime Ministers do in their long wilderness years apart from an annual appearance at the Cenotaph? In the case of David Cameron, the script could only happen in the Tory Party, where wealth, privilege and connections are everything.

The man who led Britain into the disaster of a Brexit referendum for the base purpose of holding together a fractious party, regardless of national interest, is now to represent us in the same chancelleries of Europe from which this folly removed us. It stretches irony to the limits.

Whatever kudos may attach to being a former Prime Minister will be greatly outweighed by the knowledge in European capitals that he is also the man who caused so much trouble in the first place. How, within the government of which he is now part, can he make common cause with Brexiteers – including Sunak – who built their political careers on destroying his Premiership?

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Once again, the force which drives this absurdity is that the Tory Party is split and plagued with plotting while another weak Prime Minister flounders to shore up his position. Short-term opportunism in restoring Suella Braverman to high office has rebounded spectacularly, so Sunak is now forced into another set of fixes to keep himself in a job.

And what has Lord Cameron, as we must now call him, done in the meantime? Like all good Tory grandees, he set about the pursuit of even more mammon than that which birth had generously bestowed upon him. Predictably enough, his judgement was then not very good even in that respect.

He made £7 million out of employment as a lobbyist for Lex Greensill and his dodgy investment firm before it went bust leaving vast mountains of debt behind. This was very much less than intended if the pyramid hadn’t collapsed but still a useful pension supplement.

We must conclude that such business derring-do only enhanced his reputation in the eyes of Mr Sunak, a kindred spirit in the maximisation of personal wealth.

It was as recently as 2021 that the cross-party Treasury Select Committee found that Lord Cameron’s lobbying (of Sunak, among others) on behalf of Greensill showed “a significant lack of judgement”. It was only because the lobbying rules had “insufficient strength” that the former Prime Minister had not broken them.

The Greensill scandal kind of faded away, as these things do. However, one certainty which arises out of yesterday’s appointment is that its entrails will now be examined afresh and nothing which emerges is likely to be to the credit of the newly-minted Foreign Secretary. Meanwhile, the rest of the world is supposed to take him seriously?

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As for any honest, competent Tory Ministers who may exist – and particularly the remaining few who opposed departure from the European Union – they must surely wonder what place they have in a party or government that regards their qualifications as inferior to those of Lord Cameron, the Brexit Prime Minister and Greensill lobbyist.

The key political point in this farce is that Mr Sunak was forced into another it by his own error in appointing Mrs Braverman as Home Secretary in spite of her well-established reputation for disloyalty and ruthless ambition.

Having walked out on Theresa May over her decent efforts to secure far better Brexit terms than those which eventually emerged, Mrs Braverman was brought back into the fold by Boris Johnson, which speaks its own volumes. After standing for the Tory leadership to burnish her right-wing credentials, she was sacked by Liz Truss (who must also be due for a come-back) for using personal channels to communicate government business; at a level serious enough to justify dismissal.

Her farewell letter to Truss now sounds strangely appropriate: “Pretending we haven’t made mistakes, carrying on as if everyone can’t see that we have made them and hoping that things will magically come right is not serious politics”, wrote Braverman.

The letter to Truss continued: “It is obvious to everyone that we are going through tumultuous times. I have concerns about the direction of our government. Not only have we broken key pledges that were promised to our voters, but I have had serious concerns about this government’s commitment to honouring manifesto commitments”.

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When Sunak succeeded Truss, that letter could scarcely have offered a clearer signal of Mrs Braverman’s continuing intentions and ambitions. Yet in order to ensure victory over Johnson, he gave her the Home Secretary’s job in which she had licence to play every populist right-wing card at her disposal and thus build her own base for a leadership bid.

Her decision to publicly undermine the Metropolitan Police at the moment of greatest sensitivity carried irresponsibility and ambition to new heights. It could only have been based on the calculation that there is a big enough market for her prejudices among Tory Party members to carry her across the line, next time round.

Brutal as Braverman’s letter to Truss was, it is likely to be tame stuff compared to her resignation speech in the Common when the knife will be well and truly turned on Sunak. And so the whole Tory psychodrama will continue.

Just as many lifelong Labour supporters looked on in dismay during the descent into irrelevance in the Corbyn years, moderate Tories in every part of Britain must now wonder what kind of freak show the party they voted for has become. They too must realise that this cannot go on and that the catharsis of opposition is necessary to define what the Conservative and Unionist Party actually wants to stand for.

We have just heard a King’s Speech which should have been a launch-pad for an election year. Instead, it was a complete damp squib, hardly noticed and already forgotten. The longer Mr Sunak hangs on, the more his Premiership will be dominated by the undignified contest to succeed him.

Far better for him to go now, make even more money and perhaps one day he could return as Foreign Secretary.