Heather Rabbatts walked into the Lions' Den at Millwall FC, and found the fighting was in the boardroom

It's the stuff of nightmares for any football fanatic: a confrontation with 700 angry Millwall fans, who have perhaps the most frightening reputation among supporters across the country. But that was what faced Heather Rabbatts at her first meeting with fans after her appointment as executive deputy chairman of Millwall Football Club two years ago.

"It was a rather daunting meeting but the fans have been great since I arrived," says Rabbatts. "They were rightly sceptical about things and, of course, me. But I cottoned on quickly that they don't want spin and bullshit. They won't get it from me. They've been great – the passion here is like nothing else I've been involved in."

Rabbatts may have been unknown to fans of "the Lions" but she had built up an impressive CV in business prior to her entry into the beautiful game: a qualified barrister, former chief executive of Lambeth Council, a BBC governor, a director of the Bank of England and a former head of education at Channel Four – all topped off with a no-nonsense reputation that has alienated and endeared her to people throughout her business career.

So why on earth head to the unfashionable pastures of Bermondsey, south-east London, to take on a club from football's third tier and risk her reputation?

Rabbatts says it must be in her roots. Although born in Jamaica, she grew up in southern London and studied at the London School of Economics. "My father is from Peckham [close to Millwall's New Den home] and I've always been a football fan. I know this area well and joining Millwall represented something very different from the usual regulatory directorships I'm offered. I've loved it so far."

The 52-year-old may have loved it but a reciprocal feeling from the fans has proved harder to come by. Only last week, one Millwall blogger claimed the board of the Division One club was "rotten from top to bottom".

Now she's under fire again – but this time she has 43,000 Millwall fans and investors on her side. They're looking to her to save the club from the latest corporate attack launched by Millwall shareholder Graham Ferguson Lacey, the corporate raider renowned for breaking up companies.

Last week Lacey, through his Sports Regeneration vehicle, tabled a raft of proposals to the Millwall board that would in effect force the company to gain shareholder approval for nearly every move it makes – and that would probably include player purchases. According to Rabbatts, the "vexatious and unworkable" proposals would cost the club £50,000 each time letters were sent to the club's 40,000-plus shareholders.

Lacey is a colourful character. Usually based in the Isle of Man, he chooses the Lanesborough, one of London's most expensive hotels, as his residence while in the capital. By contrast, glamour is in short supply at Millwall, who languish just two points and two points off the relegation zone in Division One, and there are just four games to go.

Speaking in her boardroom at the back of Millwall's stadium last week, Rabbatts says: "Mr Lacey's timing couldn't have been any worse. He clearly could have waited but has chosen the worst possible moment. I think the fans recognise that."

Fans and onlookers alike have speculated that the move is a precursor from Lacey to wind the club up and get his hands on the real estate, although he has remained tight-lipped as to his reasoning and intentions.

Millwall FC hold a 140-year lease on the ground linked to the local council, but any redevelopment plans would probably be thwarted by restrictions on the use of the property.

"The fans were suspicious of Peter de Savary [the property tycoon and former chairman who appointed Rabbatts], who by his own admission didn't really get football," says Rabbatts. "But after years of change and instability at the club, I think that the majority of the fans are behind us in what we are doing."

She is used to shoring up Millwall's defence. One of her first moves as chief executive was to secure much-needed finance for the club, bringing in John Berylson, a wealthy American sourced through advisers Seymour Pierce. Until that point Berylson had no affiliations with football, although he was a backer of the Philadelphia Eagles, the American football team.

"There were plenty of unrealistic expectations that came with Mr de Savary," says Rabbatts. "It was quite clear that we needed an injection of cash to keep the club going, and John has been instrumental in the continuation of the club."

Berylson has so far lent the club £8m – £3m of which, at a rate of 10 per cent, came last week – a week that could prove pivotal for the club as a result of the corporate raider's manoeuvres.

Lacey owns a near 30 per cent stake in Millwall, with a large portion of his position having been bought from the former chairman and Dragon's Den star Theo Paphitis.

A friend of de Savary – they were at school together at Charterhouse – Lacey portrays himself as a fundamentalist preacher and wheeler-dealer financier, with little concern about reconciling God and Mammon.

He is reported to have said in the early 1990s: "Religion is the USA's third-biggest industry." However, a former employee of his is reported to have remarked: "If I went to hell and found somebody trying to sell warrants and options on the coal supplies, it would be Graham."

Colourful he may be but his track record is mixed, as illustrated by the fate of one of his companies – Birmingham and Midland Counties Trust – which crashed in the 1980s owing millions to Northern Bank. Lacey decided to up sticks and head to the US to start again.

Since Millwall's board rebuffed his proposals last week, Lacey has not been available for any comment.

"Look, it's clearly Mr Lacey's move now," says Rabbatts. "He can redraft his resolutions. He can take his stake above 30 per cent and make a full offer. Or he can mount a legal challenge. The ball is in his court – but we've heard nothing."

If past experience is anything to go by, Lacey could stay quiet for some time. On his purchase of Paphitis's 16 per cent stake, he was entitled to take up two seats on the Millwall board – something he has never done.

"Having so keenly fought for them, we were, to say the least, surprised he didn't take either of them up," says Rabbatts with a rolling of the eyes.

It is ironic that for someone trying to get away from the mainstream corporate battlefield, Rabbatts has found herself in the centre of an old-fashioned ding-dong down at the Den.

So any regrets? "Not at all. It's difficult, and being a woman dealing with some people in this sport can be tough. But it's a challenge like no other and I love it. The passion is incredible."