The eastern end of Oxford Street in the driving rain, with its rows of stalls peddling bobbies’ helmets, saucy postcards and other tourist tat, does not make an enticing retail destination.

Cleaning this up is one of the tasks facing the New West End Company, created in 2005 to coordinate the £1.5 billion to be spent by the Government, property groups and retailers over the next five years on Bond Street, Oxford Street, Regent Street and 12 neighbouring side streets.

Dame Judith Mayhew Jonas, best remembered in the City as leader of its local authority until 2003, arrived as chair of the company at the start of this month.

It is the latest entry on a CV that looks like the accidental entangling of the careers of two, or even three, people of the same name.

Surely one person cannot have been a high-ranking City solicitor, chairman of the Royal Opera House, the only nonAmerican on the main board of Merrill Lynch in New York, Provost of King’s College, Cambridge, chairman of the Independent Schools’ Council?

Judith Mayhew, as she was called then, was chairman of the Corporation of London’s policy and resources committee for six years. This was the most powerful post in the local administration of the Square Mile.

Born in New Zealand, and a woman, she was always going to be perceived as an outsider. Her forthright manner and whirlwind energy raised the hackles of some of the old guard. She, along with predecessor Michael Cassidy and successor Michael Snyder, can claim to have transformed the Corporation.

Once a cosy gentlemen’s dining club governed by rituals straight out of Gormenghast or Ruritania, it can now claim to be accepted everywhere as the main body promoting the interests of the British financial services industry.

She arrived in the job just as the EU was preparing for the single market for financial services in Europe. Mayhew Jonas says: “The City Corporation gained legitimacy representing the City directly in Brussels. We had to make sure the 42 directives creating the single market didn’t damage London’s position as the world’s biggest financial centre.

“It was almost like having a foreign policy for a financial centre. There were times people referred to us as the financial Vatican.” She was the first woman to fill the post since the Corporation came into being after the Norman Conquest, she points out with pride. “They waited a long time.”

Her new role in the West End stems directly from this time, when she was one of the instigators of the legislation allowing the creation of Business Improvement Districts (BIDs), of which the New West End Company is the biggest so far.

The idea was based on her experience in New York, and the revival of areas such as Times Square and 42nd Street. “All that regeneration was done by BIDs, which are business partnerships working with local authorities and get their money from a top-slice off rates, after local New York ratepayers vote for it.

“I believe passionately that the centres of cities should become vibrant areas. The West End is an extraordinary cultural concept.”

Outstanding retail space exists alongside remarkable architecture, theatres, museums and other cultural centres. More than 200 million people visit the West End each year, half of them from outside the M25 and a quarter from overseas. The area is even fighting off the retail downturn, helped by those international visitors – figures out on Monday are expected to show a 2.5 per cent rise in sales year-on-year, against a decline of 8.5 per cent elsewhere.

To keep this edge, that £1.5 billion needs to be invested. It includes almost £600 million rebuilding Tottenham Court Road and Bond Street Tube stations, £500 million spent on Bond Street and £350 million on the Park House development by Land Securities opposite Selfridges.

Another challenge is coping with the environmental impact of Crossrail, when this link between East London and Heathrow finally arrives.

And there are those tourist tat shops on Oxford Street. “We have to sit down with the retailers and landowners and local authorities to work out what people want and how it can be developed,” she says.

She envisages a younger, edgier retail spread, in keeping with the media presence in the area, with some one-offs, rather than chains. “Yes there’s a demand for tourist” – there is a barely perceptible pause – “shops, and that’s important. What will emerge from the east end of Oxford Street will be viable. It’s very much watch this space.”

Judith Mayhew was born in Dunedin, New Zealand. Her father died when she was five, and it is probably significant, she admits, that her role model was a career woman. Her mother rose to become head-mistress of a highly regarded girls’ school. “At the age of ten I made a pact with my best friend. She said, I’m going to live in America when I grow up. I said, I’m going to live in London. She said, you’re so old-fashioned. She now lives in Philadelphia and I live in London. We still laugh about it.”

As a girl she took ballet lessons. “Most little girls who learn ballet dream of dancing at Covent Garden, like Margot Fonteyn. What I never imagined was that I would be chairing the board at Covent Garden.”

She arrived in London in the 1970s, the Dark Ages, she says, when lawyers did not easily move between jurisdictions. It was easier to relocate as an academic lawyer, therefore, and her first decade and a half away from New Zealand were spent lecturing, including a spell at the Sorbonne.

Once practising in the City, she was allowed by her employer to combine this with her rise to the top job at the Corporation. When she stepped down from this, she went back to academe, but as an administrator, as Provost at King’s. “It needed financial and administrative reform. I undertook that and delivered it, and in doing so obviously upset some of the entrenched establishment in the college.”

It was like the City again, a brash, female, colonial coming in to shake things up. There were rumblings over the port. She quit after less than three years, voluntarily. “I didn’t expect to stay there very long. It was a very exciting role, a difficult role.”

The Cambridge job ran parallel for some time to the unpaid role at the Royal Opera House, though this last came to an end as she took up the West End post. In 2003 she married Christopher Jonas, a scion of the dynasty that created the Driver Jonas property firm, though he left some years ago to strike out on his own. Strangely, one might think, given her staunch feminist beliefs, she took his name. “Because I wanted to,” she says simply. And did he take hers? “It wasn’t an issue.”

You have to wonder, in this ferment of driven activity, whether she ever relaxes. “I do get downtime. I garden.” They live in Victoria Square. “I walk. I don’t regard going to the opera or the ballet as downtime. That’s just my life.

“I get up and do really interesting things all day. I’m really lucky. Part of it’s paid and part of it’s unpaid. It’s just fun. I may stop when it’s no longer interesting. At the moment that’s not on the horizon.”

An earlier marriage ended without children. One has to ask whether she regrets not having a family. “No, I don’t. I often wonder what it would have been like and what my life would have been. I have the most wonderful nieces and nephews. One is said to be similar to me.”

Said niece was an internationally regarded sailor in her teens, clearly an early achiever. In her twenties, she now works for a large City law firm. You have been warned.

Dame Judith Mayhew Jonas CV

Born October 1948, Dunedin, New Zealand
1970-1989 Various academic jobs in law, UK and France
1989-1994 Titmuss Sainer Dechert
1994-2000 Wilde Sapte
1996-2003 Chairman, policy and resources committee, Corporation of London
2000-2003 Special adviser to the chairman, Clifford Chance
2003-2006 Provost, King’s College, Cambridge
2003-2008 Chairman, the Royal Opera House
2006 Non-executive director, main board, Merrill Lynch, New York
2008 Chairman, the Independent Schools’ Council
2008 Chairman, The New West End Company