Liz Truss returns - and it could be trouble for Rishi Sunak: Laura Kuenssberg

"Liz was mad but right. Rishi is wrong but competent."

Those blunt sentences come from a serving government minister - and they sum up the problem the PM may be about to face. Liz Truss is set to return to the political fray, via a Sunday morning newspaper op-ed, just four months after her rapid exit from No 10.

Her time in charge was a disaster. The financial markets melted. The shelf life of her premiership was compared, in real-time, with that of a wilting lettuce (it outlasted her).

Why on earth would she want to crawl out from under the duvet - and why would anyone listen?

Here is the official explanation from her camp: "Liz remains an active politician, keen to draw on more than a decade of experience in government as she contributes to national and international debates on a variety of issues."

So far, so vanilla. Why shouldn't a former prime minister have her say?

But here's the less official explanation from one of her political pals: ''It's human nature to want to justify what you did."

Pilloried around the country, and the world, Ms Truss wants to tell her side of the story - to explain what really happened, "not the fairytales", as one ally puts it.

It's worth noting that she's doing so in her own words in the Sunday Telegraph - a newspaper that's broadly sympathetic to her cause - and then in a pre-recorded chat for a podcast later in the week. She is not yet, despite our own invitation and no doubt many others, sitting down for live interviews with no holds barred.

Like many in her tribe, Ms Truss has never been short of that priceless political quality: a brass neck. Despite presiding over what many in the party see as one of the most disastrous political reigns in history, she is expected to argue that, essentially, she was right.

One ally says "she doesn't shirk responsibility" - but she's expected to restate her argument for low taxes and an economic shake-up.

And by arguing that she was fundamentally right, the implication is that Prime Minister Rishi Sunak is fundamentally wrong.

Another former cabinet minister and colleague of hers says that "she reckons the government is not a Conservative [government], it's a social democratic government". In certain Tory circles, that is the same as saying something very rude indeed.

Will her attempted comeback matter? You might agree with a different government minister, who says "it won't be troublesome at all, because she was a false prophet". It might even remind people, they suggest (or hope), of what they see as the madness during her short time in office, and make the public appreciate the relative calm under Mr Sunak.

Another member of the cabinet is less subtle, telling me: "She caused economic catastrophe four months ago, to say, 'let's have another go' is nuts." They add that "there are plenty of people in the party who will NEVER forgive her - she never turns up, and nobody cares".

Political parties tend to dislike even a whiff of disloyalty - another minister says that it might be an "old fashioned view, but former leaders tend to get respect and credit if they are seen to be helping the current one".

In other words - Liz, not now!

There are two reasons why the Conservatives and No 10 can't just shrug off what Ms Truss has to say.

First, Rishi Sunak's pitch to the country was to end the chaos and start anew. Whether it's Ms Truss popping up, or Boris Johnson cantering around the world, ghosts of the chaotic Conservative past are never far away. Politics is, at root, a contest to get heard - and clamour from former leaders makes it harder for the man or woman in charge to win.

And second, while nobody in the party would argue that Ms Truss went about her mission the right way, there are plenty of Conservatives who feel in their bones that her principles were entirely right. There's already an itchiness on the back benches about Mr Sunak's handling of the economy, and a rising demand for tax cuts that Ms Truss will help fuel.

The party is not in open revolt, but it's not in a happy place - as I discussed last week when the prime minister marked 100 days in office. Conservative MPs and some business groups reckon that, even with a microscope, it'd be pretty hard to find a convincing government plan to get the economy growing.

Liz Truss didn't have a mandate from the country for the rapid tax cuts she wanted - I well remember the tumbleweed in our studio when we asked her, after days of chaos, how many people had actually voted for her plans.

But remember, Conservative members did vote for her - and her ideas. That's why one former minister believes her re-appearance this weekend will cause trouble "because it will remind members they backed her, not him" - and that "the reason he is in power is because his team destroyed the fundamental principle of being a Tory - low tax - our members are still angry".

It is of course the public - all of you - not political parties who make the ultimate judgement on our leaders. The verdict on Ms Truss was fast and fierce, her premiership was over in a flash. But what she stood for remains, and can't be dismissed as a terrible political accident.

P.S. While we wait for Ms Truss' words in full, we are waiting too for Downing Street to appoint its next Conservative party chair after the sacking of Nadhim Zahawi. Several different sources whisper that no one wants to do the job - one source tells me it's been suggested to three different MPs who have all said no, another MP says "no one wants to do it", not wanting to take the blame for an anticipated battering at the polls in the May local elections which aren't that far away.

The suggestion that the job has been dangled and declined has been emphatically denied by a source involved in the discussions, who suggests the Prime Minister is in no rush and that there hasn't been any formal considerations yet. And with the potential exit of Dominic Raab from government after an inquiry into his behaviour, which could report around the end of the month, No 10 might have to fill not one, but two jobs at the cabinet table - so best to wait.