The figures are sobering. According to Thomson Financial's third-quarter survey of global mergers and acquisitions activity, released last week, the summer's turmoil in the financial markets brought a record year (value of total deals announced worldwide: $3.6 trillion) clattering to a halt. In Europe, the number of deals has dropped 45 per cent. Is the boom over?

Not necessarily, says Nigel Boardman. The talismanic Slaughter and May partner is more correctionist than fatalist. "I think we'll see credit costing more, which means that deals which are debt-based — private equity -— may not occur," he says.

"I was talking to some investment bankers this morning who had just turned down several [loans] that would probably have been accepted otherwise, because at the moment cash is king and it's not worth taking the risk.

"So I think we'll see deal flow slow down. I think we'll see a bit more restructuring work. But the market remains strong. Industrial output is rising. China, India still remain buoyant. I don't see it as a long-term collapse. I see it as a correction. Maybe debt has been too cheap."

Slaughters' refusal to conform vindicated by record profits

Tim Clark will step down as head of the UK's most prestigious law firm with profits at £2.5m per partner. Then what?

Relaxed and tanned after his annual holiday in the south of France, where he owns a home, Boardman has reason to feel upbeat. Despite the current picture of gloom, Slaughter and May has advised on $217 billion worth of deals so far this year, up 168 per cent on the same time in 2006. Earlier this year, Boardman completed the most complex deal, by his own reckoning, of his career, acting for Reuters in its £8 billion merger with Thomson.

In terms of profitability, Slaughter and May has closed the gap on the leading Wall Street firms and continues to embarrass its larger UK rivals, with Boardman and other top partners taking home a reported £2.5 million. His most famous client, Arsenal Football Club, is sitting happily at the top of the English premier league for the first time in years. Boardman was even named the City's best-dressed lawyer by Esquire magazine.

Today he wears a crisp white shirt, pale yellow tie, no jacket. We're sitting in Slaughter and May's ground floor cafeteria, an almost entirely nondescript space except for a jukebox in the corner, a gift from a client. As an interviewee, Boardman is pleasant and polite but less than voluble: he speaks in precise, measured sentences, saying as much as he needs to and nothing more. Tall and bald, his imposing physical stature and calm demeanour are an arresting combination. He simply owns the space around him.

I ask Boardman if there's a chance that the slowdown in takeover activity could bring an end to the boom in legal services that has seen the City's leading lawyers charging upwards of £1,000 an hour.

"I think the fundamentals driving increased lawyer involvement will continue," he says. "In many international transactions you're trying to mesh together, say, a German legal framework with an English legal framework. And there's increasing regulation. And both of those are drivers for continued lawyer involvement."

It hardly needs adding that he intends that Slaughter and May will remain ahead of the competition. "What you need is not to be a narrow specialist," he says, "and we try to make our lawyers multi-specialist across a broad spectrum of work. So I do everything from Thierry Henry's employment contract [before he left for Barcelona] to the renewal of diamond mining leases in Botswana to acting for Reuters on its merger with Thomson. I think we are better placed because we train our lawyers to offer a broader spread [of expertise]. And in times of changing markets that's extremely valuable."

This, in an age of increasing specialisation and commoditisation, goes against prevailing wisdom — but it also satisfies Boardman's natural inclinations. At any moment he may have as many as 60 client matters to deal with, but that could include something as small as the renewal of a chief executive's contract. Among his clients, Boardman acts for ten FTSE100 companies.

Unlike some deal lawyers, Boardman is not averse to the technical, so-called "black letter" aspects of practising law, and says he enjoys that as much as he does sitting around a board room table thrashing out the details of a billion pound takeover. "That's the thing about the law, it's got everything you want," he says. "It's got the people aspects, it's got the intellectual challenge."

Boardman, who grew up near Leicester, wanted to be a lawyer for as long as he can remember, even at school. He studied history at Bristol University before attenting the College of Law. He joined Slaughter and May in 1973 but left soon after for the investment bank Kleinwort Benson (now part of Dresdner Kleinwort), where he worked under Sir David Clementi, the Prudential chairman and architect of the Government's proposed legal service reforms. Boardman speaks fondly of Sir David, but he left Kleinwort Benson after only a year because he found the role "too marketing-oriented", too focused on generating new business than "adding value" for clients.

He returned to Slaughter and May, where he became a partner in 1982. Since then, he has become not only the most celebrated takeover lawyer in the City but an emblem of the firm's unrivalled success.

Much is said about Slaughter and May's distinctive, stubbornly nonconformist culture — their refusal to open offices overseas while competitors fall all over themselves to expand globally; the fact that they don't have a press office; the fanatical loyalty they inspire in their lawyers (one competitor describes the firm, admiringly, as "almost Jesuitical") — but Boardman proffers a more mundane formula for their success. Hire smart, hard-working people, train them well, instill a sense of duty, expose them to the best clients, reward them richly and let them get on with it.

"If we adopted a snooty, stuck-up attitude you would end up with the wrong recruits and you wouldn't survive," Boardman says. "We are a meritocracy.

"We want the best people to apply to us and to genuinely give them as much help as they need to become good at their job. I wouldn't want the attitude to come over that we only take Etonians, Oxbridge graduates, firsts. None of that is true. I got a 2:1 at Bristol in history. Steve Edge, our head of tax, got a 2:2 at Exeter. It's about ability, it's not about pedigree."

Can that culture survive as the legal industry becomes more corporate?

"We're not different because we are stupid," he says. "We're different because we think it's the right way to be. If it became clear to us that there was a better way to be, then we'd switch. It's not a religious belief. It's a business judgment and business judgments can change.

"I think the demand for high-quality, individually-tailored, highly-committed legal services will remain the same. If we continue to do that, I don't think clients will mind whether we wear space suits or togas. Actually, clients don't care about our strategy — and rightly. I mean, why should they?"

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