Sharon White is interested in power. Elbow power, to be precise. The new boss of Ofcom, the regulator which oversees telecoms, broadcasting and postal services in the UK, took to the stage at a conference organised by the campaign group Which? last Thursday. It was time, she said, to give “real power to the elbow of consumers”. She may have waited three months to make her first public speech, but the woman who was until last year George Osborne’s public spending cuts enforcer at the Treasury came armed with two initiatives that look set to have an immediate impact.

Broadband customers will now have the right to walk away from contracts when the speed of their connection falls below acceptable levels. And households will be able to switch landline and broadband provider more easily – with responsibility for the transfer in the hands of the company the consumer is moving to. Even the Daily Mail – generally not a fan of regulators – was impressed. In a leader comment headlined “A Watchdog to Watch”, the paper cheered: “If Mrs White succeeds in forcing the industry to be fair to customers, this spirited, churchgoing daughter of Jamaican immigrants will prove herself worth 10 times the identikit Blair crony she replaces.”

White’s predecessor Ed Richards, a one-time policy adviser to Tony Blair, was well liked at Ofcom. But those in the know say the speed at which White is working has left other regulators for dust. A keen runner who travels to the office in trainers, she has indicated that her attention will shortly turn to ensuring quicker switching between mobile networks. “Ofcom in the past hasn’t wanted to do things at a pace that will upset the industry,” says one who has worked with her closely in recent weeks. “She needed to set the tone in this period, and she’s not wasted time. That’s refreshingly different. She’s really enjoying being out of the grind of a Treasury managing austerity. She is now in the world of the possible.”

“I was very clear that I wanted to make consumers and citizens the subject of my first public speech,” she told her audience last week. White came to the conference armed with something else – a change of shoes. With a frame pushing six foot, she was conscious of towering above the crowd in a group photo and slipped into flatter footwear for the picture. But the Cambridge-educated economist is no shrinking violet. On March 23, her first day at Ofcom, she commandeered the canteen, the largest space in the building, to address the troops. The tables were cleared away and all 790 staff, including those working in the Wales, Scotland and Northern Ireland offices, were invited to come and listen. Rather than shouting from one end of the room to the other White stood on a small stage in the middle of the crowd and told her staff – the economists, the lawyers, the market researchers and radio technology experts – that they were all there for one reason, to serve the citizen. This is music to the ears of Charles Dunstone, the founder of Carphone Warehouse and chairman of broadband and pay TV group TalkTalk. The telecoms business is currently in the grip of merger fever. During White’s first week in the job the Three network snapped up 02, reducing the number of mobile operators from four to three. Now Vodafone and the big US international cable group which owns Virgin Media are considering swapping assets. The outcome is currently unclear – the mobile phone firm might enlarge its UK business – or exit altogether.

The biggest beast to emerge from this round of reorganisation is BT, which is buying rival EE in a £12.5bn mega-merger. The new company will control 40% of all spending on phone and broadband by households and businesses. The worry is that fewer players will mean higher prices for phone calls or Premier League football coverage.

“We need a tough, strong Ofcom fighting for competition, so that new entrants can come to the market like we did,” said Dunstone. “There haven’t been any big new entrants recently and we want that environment back.” He believes that BT risks investing too much in football and buying EE when it should be improving the reach and speed of its broadband network.

White is listening. Her postbag, she said, “shows that people are sometimes frustrated by the service that they are getting. Across the UK, going on for one half of [small to medium enterprises] have yet to be offered access to superfast broadband.”

White’s parents were members of the Windrush generation, leaving Jamaica for Britain in the 1950s. Her father was 15 when he arrived and her mother just 11 years old. She was born in east London and grew up in Leyton where she attended a girls’ comprehensive school. At Fitzwilliam College, Cambridge, her contemporaries included the Labour leadership hopeful Andy Burnham.

A regular churchgoer, she gained a masters in economics from University College London before going to work for a church in a deprived part of Birmingham. In 1989 she joined the civil service, where her first job was in the Treasury. It was there that White met her husband, fellow economist Robert Chote, then a journalist with the Independent. Today he is chairman of the Office of Budget Responsibility, set up by George Osborne to provide independent forecasts about the state of the economy and public finances. Until White’s move to Ofcom they were known as “Mr and Mrs Treasury”.

Asked about whether the ultimate Whitehall power couple spent much time talking shop, Chote once said: “Not a great deal. It’s mainly who’s picking the kids up, who’s dropping the kids off and why there’s no milk.”

They married in 1997 at the British embassy in Washington DC, when White was working for the ambassador Sir John Kerr and Chote for the International Monetary Fund, and now live in Tufnell Park, north London. Their two young boys have attended a local state primary, with both parents pitching in on school runs and bedtime stories. From the birth of her first son, White managed a four-day week in the office, even as second permanent secretary to the Treasury. At Ofcom she is working “full time, but flexibly”.

Labour MP Frank Field, who locked horns – amicably – with White while a minister at the Treasury, testifies both to her toughness and her sense of public service. He has said of Chote and his wife: “They have never undertaken an activity for monetary ends. They have both carved out areas of expertise with a huge sense of old-fashioned decency – and made public service cool again.”

While White is unlikely to have been lured to Ofcom by money, she will be earning substantially more there than the prime minister. Her salary is £275,000 a year, and is likely to be boosted by bonus payments and pension contributions – her predecessor Ed Richards earned £393,000 in his last full year in the job.

In the civil service White spent time mentoring young women and rebuilding teams to increase the diversity of staff. It is a practice she has adopted at Ofcom, where she is already being shadowed by a number of junior staff. The regulator’s white, male-dominated ranks could be braced for a shakeup.

So far telecoms companies have been impressed by White’s rapid grasp of detail. She has requested site visits and even diagrams of network infrastructure. But not everyone in the business is an undiluted fan. “She’s engaging, sharp, and has very firmly nailed her colours to the consumer mast,” said one executive. “There are things that are good about that. But that will need tempering around the investment agenda in the longer term. You can’t go too far down that road.”

The most controversial decision facing White will be deciding whether to divide BT in two. Many rivals want the firm’s Openreach business – which builds and manages the BT network that companies like TalkTalk and Sky rely upon – to be made independent.

An equally big question hangs over the BBC. Rona Fairhead, chair of the BBC trustees, has called for her committee to be abolished and replaced by a more arms-length regulator. Some – though not Fairhead – say that job should go to Ofcom. The decision will be taken by culture secretary John Whittingdale, in consultation with the cabinet.

One senior TV executive says that Ofcom chair Patricia Hodgson believes the BBC is too time-consuming, political and complicated for her already busy organisation to take on. But the executive reckons White’s stance is a little different: “The mood music I’ve seen Sharon give in public is neutral – the feeling that if she is given it she will deal with it”.

White has been tipped for an eventual return to Whitehall, where many think she could become the first woman to head the civil service – but an entanglement with the BBC may not be the best route to the top.

Additional reporting by Mark Sweney

THE WHITE FILE

Born in east London. Her parents came to Britain from Jamaica as children, and settled in Leyton. Educated at a local comprehensive, Cambridge University and University College London. Married to Robert Chote, chairman of the Office for Budget Responsibility. Two children.

Best of times Celebrating her wedding to Chote in 1997 in the halls of the British embassy in Washington DC. Her appointment to the job at Ofcom.

Worst of times Reviewing how her own colleagues in the Treasury were paid as part of the coalition’s spending crackdown.

What she says “When Ofcom was established, access to a reliable internet connection or mobile phone was a ‘nice thing to have’. Now ...it has become a necessity in the same way as gas or electricity or running water. “

What others say “She is one of the civil servants who do not try to flannel. She is straightforward and speaks in plain language. A breath of fresh air.” Labour MP Margaret Hodge, outgoing chair of the public accounts select committee.