The game's first lady departs after winning her Blue riband

In true blockbuster-movie fashion, giant posters have gone up around Birmingham, even near Villa Park. "Goodbye," they announce in large capitals. "Thanks for all your support over the last 17 years."

It could be Gone With the Wind, albeit without the steamy clinch between Scarlett O'Hara and Rhett Butler, and very soon Karren Brady and David Sullivan will be. Images of Birmingham City's high-profile managing director and co-owner adorn the billboards, her looking meaningfully towards the horizon while he claps, frowns and bites his lips, perhaps wondering whether the supporters will answer their "goodbye" with "and good riddance".

Brady and Sullivan, along with fellow director Ralph Gold, have designated today's visit by Bolton Wanderers as their farewell game after 16 and a half years at St Andrew's. To mark the occasion, Birmingham have reduced seat prices, although Brady will miss her own leaving-do because she is filming the next series of The Apprentice.

Sullivan, the soft-porn publisher from Essex who bought Birmingham in 1993 when liquidation loomed, admits he will be "emotional", possibly even "tearful". But his departure, to make way for Carson Yeung and the Hong Kong-based Grandtop International Holdings, may not be widely lamented.

Many "Bluenoses", although grateful to Sullivan and David Gold for resuscitating a moribund club, argue that the 60-year-old did not continue to invest the funds necessary to make Blues a force in the Premier League rather than a team destined for an annual struggle against relegation.

Brady, 40, is going to be missed, however – and not just by Birmingham. The Premier League will lose its main, almost only female presence. In her time the English game has had women physios, press officers, club secretaries and reporters, plus, of course, a celebrity club-owner, Delia Smith, and an excellent broadcaster, Jacqui Oatley.

Yet Brady, who is married to the Burton Albion manager, Paul Peschisolido, and has two children, made greater inroads into this male-chauvinist domain than any of her contemporaries. Loyal to the last, she defended Sullivan in her Sun column under the strap line "The First Lady of Football". Her employer was "no favourite of the fans", she conceded, but they "grossly under-estimated his energy, imagination and enthusiasm".

Those, coincidentally, are only a few of the qualities she has brought to her pioneering role at Birmingham since Sullivan appointed her to run the club as a 23-year-old with a background in selling advertising.

Critics, comparing Birmingham's modest investment in players over the past five years with Randy Lerner's bankrolling of Martin O'Neill at neighbouring Aston Villa, allege that penny-pinching is another of her attributes. Brady makes "no apologies for running the club as a business" – being in the red is "an own goal" – but maintains that Birmingham were the 10th biggest spenders over the summer,

Her entrepreneurial acumen is manifested almost everywhere you look at St Andrew's. The shabby, rotting hulk of a ground she and Sullivan inherited is now a bright, blue, modern citadel, with swish offices, suites and bars, not to mention new stands on three sides.

When the pair arrived, Blues were on a downward spiral to the Third Division, playing to crowds of 6,000 and training on park pitches. Last month they began their third spell in the Premier League, the first lasting four seasons. Crowds are down again but still average 22,500, and part of Brady's legacy is the club's own training ground on the green-belt Wast Hills site. Her duty of balancing Birmingham's resources against the transfer demands of their managers brought her into conflict with Barry Fry, then Trevor Francis. The relationship with Steve Bruce proved more productive –"dynamic" she called it – but Yeung's failure to give Bruce assurances about a new deal when he made his initial bid two years ago cost them his services.

Sullivan's restlessness led him to remark in 2007 that "the honeymoon [with the public] is over – we're at the divorce stage now". He also made outspoken attacks on highly-paid players. Things came to a head when the crowd turned on him after relegation 16 months ago, and he, in turn, lambasted Bruce for leaving Alex McLeish "quantity not quality".

David Gold, who will remain at St Andrew's, had hoped to convince Grandtop to persuade Brady to stay and ensure continuity. She wanted to move on. Meanwhile, Yeung's representative, Sammy Yu, is in town preparing for the transition. The warmth or otherwise of the "goodbye" Sullivan receives today may be a pointer to the long, hard road ahead.