Liz Truss, the International Trade Secretary, proclaims the brilliance of the free trade agreement she has just signed with Japan. According to a video posted by her on Twitter, the deal, the first of its kind since Brexit, is “a win-win” and “just a glimpse of global Britain’s potential”, for it paves the way to other deals.

Experts observe that the economic benefits of the first deal are likely to be “very small”, and mockery erupted when the Department for International Trade tweeted, during an episode of The Great British Bake Off, the questionable assertion that soy sauce from Japan will become cheaper.

Nonetheless, it’s worth remembering that opponents of Brexit lauded the EU’s trade deal with Japan, while taking side-swipes at the UK’s “untested, yet still somehow flailing, negotiating team”.  Truss has delivered a trade agreement which some Remain supporters said wouldn’t happen before a trade deal was complete with the EU.

It is extraordinarily difficult to sing the praises of a trade deal. Rosy assertions about future prosperity have yet to be confirmed by events, and are countered by grim forecasts from depressed Remainers, while the voluminous details of what has been agreed are deeply technical and strike the public as intolerably dull.

In the present Cabinet, only Boris Johnson, Michael Gove and perhaps Rishi Sunak could give a speech about trade which would raise people’s spirits.

Like most of the rest of her ministerial colleagues, Truss is a dull speaker who never seems to get much better.

But she has the virtue of never appearing to get downhearted. She possesses a seemingly invincible perkiness.

Last summer, while contemplating a bid for the Tory leadership, she told The Mail on Sunday that as a woman in politics, “you have to be prepared to put yourself forward because nobody else is going to”.

In her case, this could well be true. A senior Tory this week told ConservativeHome: “Her longevity in Government is a mystery to virtually the whole parliamentary party.”

The senior Tory had perhaps failed to observe that in the most recent ConHome Cabinet League Table, Truss, with a net satisfaction rating of +69.7, was second only to Sunak, on +81.5, with Dominic Raab in third place with +59.7 and Gove fourth on +56.4, while the Prime Minister got -10.3.

At the age of 45, Truss is a veteran, the second-longest serving member of the Cabinet, which she joined as Environment Secretary in July 2014, a record beaten only by Gove, appointed Education Secretary in May 2010.

Perhaps that explains why the editor of ConHome possesses a seemingly inexhaustible appetite for profiles of Truss. The first appeared in March 2014, when she was a rising star of the 2010 intake, a tough-minded Thatcherite northerner who had been educated at a comprehensive school and was tipped by some as a future leader.

The next profile appeared in March 2017, by which time she was Lord Chancellor and Justice Secretary, and the judges were furious with her for failing, as they saw it, to defend judicial independence against attack by The Daily Mail.

Three months later, she was demoted to the post of Chief Secretary to the Treasury. Here she continued to fight her corner, and on occasion to express her disrespect for Cabinet colleagues (including Gove, by now Environment Secretary), as in this lecture, delivered at the London School of Economics in June 2018:

“I’ve never liked being told what to do. And I don’t like to see other people being told what to do. Britain is a country that is raucous and rowdy…

“I see it as my role as Chief Secretary to the Treasury to be on the side of the insurgents – I see myself as the disruptor in chief! Because British people love change…

“And government’s role should not be to tell us what our tastes should be.

“Too often we’re hearing about not drinking too much…eating too many doughnuts…or enjoying the warm glow of our wood-burning Goves…I mean stoves.

“I can see their point: there’s enough hot air and smoke at the Environment Department already…

“we have to recognise that it’s not macho just to demand more money. It’s much tougher to demand better value and challenge the blob of vested interests within your department.

“Some of my colleagues are not being clear about the tax implications of their proposed higher spending.

“That’s why, in next year’s Spending Review, I want to take a zero-based, zero-tolerance approach to wasteful spend.”

In May 2019, while dipping her toe in leadership waters which turned out to be too chilly for her, Truss spoke of “a need to build a million homes on the London Green Belt”. On an earlier occasion, to an American audience, she had spoken with relish of a world in which “no one knows their place, no one fears failure, and no one is ashamed of success.”

This gung-ho side of her, the relish she takes in assaulting the cosy world of received pseudo-liberal opinion, her longing to let the free market rip in order to produce the wealth which alone will rescue the poor from over-priced housing and allow them to feed their children, find a ready assent in Johnson.

He too is a disruptor, who wants to unleash the animal spirits which have been crushed by socialist planning laws, and who favours tax cuts for everyone, including that most despised group, the better off.

Truss became the first Cabinet minister to declare for Johnson, and as Stephen Bush some time afterwards related in The New Statesman:

“During his bid for the leadership, Liz Truss advised Johnson on economic policy, and was the architect of plans to cut taxes for people earning over £50,000. Civil servants dreaded a Johnson government because they found Truss’s tenure as Chief Secretary to the Treasury under Theresa May exhausting, for reasons ranging from her demanding work schedule to her habit of asking officials multiplication questions at random intervals. Few dispute that she would have been able to do the job effectively. But Johnson discarded her as his chancellor-designate in part because of the row the tax plans caused, and in part because Sajid Javid was more willing to spend freely.”

Truss was more suited to the go-getting task of pursuing free-trade deals, as part of a global Britain strategy in which – despite having voted Remain in 2016 – she has the merit of actually believing.

She holds another post, Minister for Women and Equalities, and here too she is of value to Johnson, by holding the line against fashionable opinions which if adopted by him, would destroy his credibility with the former Labour voters in the Midlands and the North who handed victory to the Conservatives last December.

Truss is conducting a review of the whole field of equalities and diversity policy, and at Downing Street’s behest, has already refused to allow self-definition by transgender people under the Gender Recognition Act.

Crispin Blunt, Conservative MP for Reigate, was furious with her:

“Does she appreciate that trans people cannot discern any strong or coherent reason for this screeching change of direction?

“Does she understand the anger at the prospect of them receiving their fundamental rights being snatched away?”

But the Labour Party leadership has declined to pick a serious fight over this issue, for it knows that many old-style feminists are aghast at the idea of trans men being allowed to declare themselves women and enter women-only spaces.

So Truss, with her odd mixture of indiscretion and obedience, her contempt for liberal groupthink, love of freedom and faith in free trade, is in many ways a useful ally for Johnson.

Her detractors will continue to say she has only got where she is today because the Prime Minister needs a reasonably high proportion of women in senior posts. But it would be fairer to say that she has got there because she had the gumption to declare her loyalty to him in June 2019, and is in many respects a kindred spirit.