Four years ago, Helen Weir was being tipped as the first woman to run a top UK bank. Now she's being named as a potential successor to Marc Bolland at Marks & Spencer, which would make her the first woman to head a top-flight UK retailer.

Talk of Weir’s succession to the chief executive’s chair at M&S might be a little premature. After all, her appointment as finance director at the group was only announced on Monday and it looks as though her current employer, the John Lewis Partnership, will be holding Weir to her six-month notice period rather than hand over a key executive to a major competitor for the crucial Christmas trading period.

But, as Bolland struggles to convince the City that his turnaround strategy is working at M&S, thoughts regularly turn to who might replace him should major shareholders finally run out of patience. Still Britain’s biggest retailer by market share, M&S’s performance over Christmas will clearly be key to how much longer Bolland can hold on to his job at the group, which he joined just over four years ago.

At around the same time as Bolland was stepping up at M&S, Weir was being tipped to take over the running of Lloyds Banking Group, which she joined as finance director from Kingfisher in 2004. But she lost out to Antonio Horta-Osorio, and left the bank shortly afterwards.

Her next move, which involved a substantial pay cut, was to the employee-owned John Lewis Partnership, also to the role of finance director.

At M&S, Weir will receive a basic annual salary just of £590,000 – £11,000 more than her predecessor – and will also be given a one-off payment of £188,500 to compensate her for the pension she is giving up to join M&S. She may also be compensated for foregoing her bonus at John Lewis.

Although Weir is unlikely to arrive at M&S until almost halfway through next year, the appointment has been well received in the City. The finance director's chair at M&S has been empty since September when Alan Stuart, who announced his departure for Tesco in July, was allowed to leave early to help the beleaguered supermarket group through its accounting scandal.

One of the highest-profile women in the City, Weir has made no secret of her ambition to take on the role of chief executive of a major company. When still at Lloyds, she said: “I would like to run a business at some stage. I would like the top job.”

Such honest ambition is refreshing, but possibly somewhat unnerving for colleagues and Weir has a formidable reputation. She also hit the headlines more than a decade ago, when it emerged she had received a hefty relocation allowance of £340,000 from the B&Q DIY group, Kingfisher, for a move of just 40 miles from Hampshire to Buckinghamshire.

Internal contender

Weir was door-stepped by reporters and the brush with the press left her so rattled that she apparently considered quitting publicly-listed companies for the anonymity of private equity owned businesses.

Bolland is clearly pleased she decided against that course, declaring himself “delighted” with the appointment, saying Weir was “extremely well qualified and brings a wealth of relevant financial, retail and consumer experience”.

She won’t be the only woman at M&S in with a chance of the top job. Laura Wade-Gery, who was brought in from Tesco just over three years ago to head up the digital operations at M&S, was also put in charge of the UK stores network earlier this year, and is seen as a leading internal contender.

Wade-Gery was one of Bolland’s first major appointments at M&S and her recruitment was regarded as a coup, as she had been widely regarded as a future CEO at the supermarket group.

For Bolland, meanwhile, pressure has eased a little recently, following news of the group’s first increase in profits in four years, albeit a modest one. But clothing sales were still down and Christmas will be the real test.

Fiona Walsh is business editor of theguardian.com