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“This may sound ridiculous, but I do believe that I’ve been called to be a lawyer.” Peter King, a corporate partner at Shearman & Sterling in London, knew within two days of starting his law degree at Cambridge that he had found what he wanted to do for the rest of his life. “I don’t know why,” he says. “There was just some chemistry.”

King, 48, specialises in mergers and acquisitions, last year advising Borsa Italiana on its merger with the London Stock Exchange and Credit Suisse on its role in the attempted £11 billion takeover of Sainsbury's by a Qatari-backed investment fund.

But he doesn't fit the stereotype of the macho deal maker: a language student before he turned to law, he is fluent in French and German and reads Latin, Hebrew and ancient Greek. He likes gardening and classical music, sings in choirs, plays the clarinet and the tenor saxophone, sponsors a baroque orchestra. How does he find time? “I actually believe that lawyers do a better job when they’re not just doing law all the time,” he says. "And I'm quite quick."

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If King’s remark about being “called” to be a lawyer makes him sound religious, that's because he is. He is the chair of the board of deacons at his local Baptist church in Dulwich, in south London, where preaches and leads services. He is studying for a degree in theology and sponsors several faith-based charities, including the UK arm of the Tutu Foundation, a group founded to spread the work of Archbishop Desmond Tutu, the South African spiritual leader; a group that helps Aids victims in Africa run by his brother-in-law, a missionary in Nigeria; and a group that promotes evangelism in Britain. His wife, an accountant, runs the Association of English Cathedrals.

How does King reconcile the highly-paid, high-octane world of corporate finance with Christian values? “I actually feel the law is, by definition, an ethical profession,” he says. “Integrity is at the heart of what we do. I find what I believe as a religious person with what I do as a lawyer quite easy.”

He will, he adds, give some of his money away. “It’s about what you do with the money when you’ve got it. I believe in using my money for the benefit of other people.”

King was born in Nottingham into a humble family; neither of his parents went to university. He joined Linklaters in 1981 after graduating from St John’s College and was one of the firm’s rising stars when, in 2003, he defected to Shearman.

American firms at the time were rapidly expanding their presence in London and luring high-profile partners from English firms with the promise of staggeringly lucrative packages. King insists he was happy at Linklaters, but he was wary of being forced into management or made to retire early. “I’m still enjoying what I’m doing,” he says. “I don’t want someone in three year’s time saying, ‘What are you still doing here?’”

Moreover, he was “fascinated” by the emergence of American firms in London. “It seemed to me that anyone who could crack US-UK integration would have a very, very good business,” he says.

Shearman’s aim in London is to compete with the leading English firms for high-value work, offering advice on both UK and US law while remaining relatively lean. It is an approach that has yielded some success, winning over clients such as the Royal Bank of Scotland, International Power and Corus, but King admits it is hugely amibitious. “It requires much longer than we’ve been doing it so far,” he says. “We’ve had our ups and downs, a few setbacks with people leaving, but we’re now a very stable team and that’s starting to show through in the results and the feedback we’re getting from clients.”

However long it takes Shearman to break into the London elite, King believes American firms have become a permanent feature of the legal landscape. He rejects the widely-held view that the market will come to be dominated by only a handful of global full-service firms. “We used to sit around and say there would only be three or four firms at the top,” he says. “I remember having that discussion ten years ago. Now, I’m not so sure.”

Deals have become more complex, clients more conscious of conflicts. That means there are roles for more, rather than fewer, big law firms. Last year on the Sainsbury's bid there were seven law firms around the table. He also points out, with some relish, that only one of them (Linklaters) was English; the rest were US-headquartered.

But for all the talk about the rivalry between American and English firms, King says the biggest difference between working for Linklaters and Shearman is simply the scale. Shearman has only 150 lawyers in its London office. King prefers the intimacy. “I know pretty much everyone in the office,” he says. “I may not speak to all of them every day, but I know who all of them are.”

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