The housing secretary has admitted paying the wrong amount of tax on a house.

That is pretty much the worst headline conceivable about any housing secretary, let alone Angela Rayner, who is also the deputy prime minister and spent years as Labour’s sleazehunter-in-chief.

That’s the straightforward fact which makes this such a damaging, indeed career-threatening, episode for Rayner.

Other elements are not quite so straightforward. The case was untypical because it involved her divorce, and a trust Rayner and her ex-husband had set up to provide for her son, who has lifelong disabilities.

Crucially, Rayner is adamant that she sought advice from a lawyer about the stamp duty liable, and has only now learnt from a different lawyer that that advice was wrong. It is on that basis that she is not resigning.

It is no doubt on that basis as well that Sir Keir Starmer full-throatedly defended his deputy at Prime Minister’s Questions this afternoon – though remember that while he could sack her from her government positions she has an independent mandate as deputy leader of the Labour Party which only she can give up.

It is also on the basis of the flawed initial advice that Labour officials, ministers and MPs mostly seem as of this afternoon to believe that Rayner will probably survive the independent investigation into whether she has breached the ministerial code.

Whether she will survive in the court of public opinion is being treated as a separate matter altogether.

There are few attacks more devastating in politics than the charge that there is one rule for them and another for the rest of us. That’s why Labour politicians, including Rayner, deployed it so often in opposition themselves.

Within the Labour Party, Rayner is – as one senior figure put it this afternoon – “Teflon”.

Having backed Sir Keir’s more left wing leadership opponent back in 2020, she and the PM have had at times a difficult, and occasionally extremely difficult, relationship.

But she has made herself absolutely vital to his political project. As housing secretary she is responsible for delivering on one of his most important policy pledges, and as deputy prime minister she has been used to reach parts of the party the PM cannot, for example when she was tasked with helping to defuse the welfare rebellion earlier this year.

Sir Keir will be desperate not to lose her from government, and she is clearly desperate not to go.

But that is no longer entirely in their hands.

This is certainly not how “phase two” was meant to begin.