Karen Bradley’s appointment as ­Secretary of State for Culture, Media and Sport came as a Westminster surprise. Unexpected that is, except to Theresa May’s tight-knit coterie, who understand the key operating principles of her rise to the leadership.

The new Prime Minister keeps good faith with those she deems loyal, level-headed, and unflashy. To that extent, the new culture secretary is a thoroughly Conservative appointment of the old school: she is a trusted adjutant, rather than an ideologue or previous expert with hobby horses to ride.

As a former shadow culture secretary herself in the mid-2000s, May is confident that she knows enough about the broad brief to make the major decisions.

Bradley’s rise is a case of the pendulum swinging from an ideological culture secretary to a technocrat. Her predecessor, John Whittingdale, had a long history of seeking a smaller BBC but May has in the past spoken more warmly of a “strong BBC”, “important for the UK and the broadcasting industry as a whole”.

The elevation of a more moderate ministerial voice reflects May’s general approach: avoiding unnecessary controversy as she wrestles with finding a deliverable Brexit plan that does minimum damage to UK plc.

A rung under May’s closest ally, Philip Hammond, who has been promoted to Chancellor, the unassuming Bradley is the politician that May trusts to act instinctively with the grain of her own interests.

"Theresa May invites few colleagues for a gin and tonic after work, but Bradley is one of them."

“She is one of the few people May would spend time with outside the day job,” notes a fellow minister. May invites few colleagues for a gin and tonic after work, but Bradley is one of them.

In part, this is because May has a personal affinity with the hard-working Bradley. She is a comprehensive-­educated maths graduate of Imperial College London, who has slogged away as a senior tax adviser at KPMG.

This relative newcomer – she was elected to the Commons only in 2010 – combines the talents of a flinty politician with high intelligence and a low profile. It was not always certain that she would reach the upper ministerial slopes. Westminster watchers (in this case, me) noted that her main rival for higher office was Andrea Leadsom, a gutsy Brexiteer briefly a candidate for the Tory leadership.

As a former accountant, Bradley knew more about financial projections than many of those in more senior decision-making jobs. “She is very calm and focused, and can juggle numbers at top speed,” notes an MP who sat with her on the Work and Pensions Committee.

Her drawback, in a job that involves sweetening many perpetually annoyed groups in the arts, media and sport, has been a lack of discernible personality. But a similar frosty detachment has not stopped her governor rising to the top.

BBC bosses might take note. It is Bradley’s ability to master figures and their context that is one of the main reasons she has been given media fiefdom.

The chief focus of the role, as far as May is concerned, is to steer through Charter renewal based on the recent BBC white paper. As for culture and sport, it would be hard to see why Bradley, whose only known cultural indulgence is crime novels, is any better qualified than the next minister.

Policy-makers close to Team May point out that unravelling Charter renewal is not a priority for No 10. Some trailing wires, however, are in evidence and May requires a trusted ally to sort them out.

In essence, the trade-off in the white paper is a deal struck by BBC Director-­General Tony Hall: in return for no major reduction of the corporation’s scale and activities, the BBC will pay for the £650m-plus cost of free TV licences for the over-75s.

Some sticking points remain, however. One is the threat of government-­appointed members to a new BBC unitary board. The Government’s original instinct was to leaven the BBC’s tendency to appoint unchallenging Trust members, who minsters saw as inexperienced in the commercial sector and too close to the corporation’s status-quo inclinations.

But government appointees run counter to the long-standing principle of BBC independence. They would be resisted fiercely by Lord Hall and prominent corporation supporters.

That, senior BBC sources suggest, might see May trading away the idea of political appointees or agreeing to farm it out to an arm’s-length committee.

But in exchange for what? The detail of Hall’s “Compete or Compare” strategy on independent production might face further scrutiny. Opening up radio to a 60% quota for independents by 2022 worries internal suppliers.

“Charter renewal is like fiddling with a piece of embroidery – you pull one thread and the rest becomes unstitched.”

Will Jackson, Managing Director of the trade body Radio Independents Group, says: “I’d expect the focus to be on ensuring distinctiveness in BBC Radio. The speedy opening up of the schedules to competition from independent producers will be vital.”

BBC Television, mired in arguments about market impact and “distinctiveness”, may yet find itself with a fight on its hands over “competitive scheduling” of popular shows such as Strictly Come Dancing and the effect it has on commercial rivals.

But, says one Tory backbencher, “Theresa does not strike one as the woman who fancies a big ruckus over Strictly – not least because she is an occasional viewer herself”.

As for the plans for BBC Studios, the likelihood is that a selectively arranged market will emerge in which ring-fenced shows cannot be contended for. Other, less well-known programmes are more likely to be farmed out to indies in order to make the plan work.

Independents fear that the arrangement is still too dependent on commissioners who want to protect the output of existing BBC departments.

The overall impression is that the Government is unlikely to revisit Charter renewal at this stage, suggests a senior BBC management figure: “It is like fiddling with a piece of embroidery – you pull one thread and the rest becomes unstitched.”

Similarly, there is scant sign of interest in resurrecting the mooted sale of Channel 4.

Instead, the main concern of the new DCMS team answering to a PM keen to underline her understanding of the UK outside London and the South East concerns the nations and regions. Bradley will want to ensure that the BBC achieves greater diversity of supply without simply “brass plating” companies based in London.

Incidentally, as an MP for Staffordshire, she embodies the rise of the non-metropolitan, May-era Tory.

May is not always inclined to accept the Cameron-Osborne legacy. One clue to her thinking might lie in Bradley’s de facto deputy, Matthew Hancock, as minister of state with a focus on digital innovation.

As the corporation’s new regulator, Ofcom will oversee competition questions. But there are indications that the new ministers will be keen to ensure that Ofcom is rigorous in doing so.

“Hancock’s commitment to spur on digital innovation [an area he championed at the Treasury] means that he has grounds to look out for outcomes that end up stymying innovation or competition,” says an official. “Ed Vaizey [his Cameronian predecessor] saw the job as persuading the culture establishment that not all Tories were out-of-date philistines. Hancock is a tougher, more driven character with a determination to make his mark on the digital economy, and that can rub up against the interests of the BBC.”

But Hancock will be constrained by the realities of May’s position. A small Commons majority, plus the combination of running Brexit wars and the personality of his boss make it unlikely that he will rock the boat.

A friend of Bradley says: “She is ambitious enough to be wary of the fate of previous incumbents Maria Miller or Sajid Javid, neither of whom left much of a mark, but ambitious enough to know that the job can be a stepping stone to greater things.”

Remember Jeremy Hunt, elevated from culture secretary in 2012 to health secretary. And, crucially, that the PM will always take Karen Bradley’s call.

Anne McElvoy is senior editor at The Economist.