He blinks nervelessly behind steel-rimmed glasses. Brock, sitting at a meeting table in his office opposite the giant Stella Artois brewery in Leuven, Belgium, is not going to sell himself hard. His passion outside work is scuba diving, and at times it feels as if he is just swimming through our conversation, waiting to see what he will harpoon first.

But at Cadbury Schweppes, where he rose to become chief operating officer, he had a reputation as an expert globaliser and inexhaustible traveller. Now at Inbev, the monster beer group he put together by merging Belgium’s Interbrew with Brazil’s Ambev in 2004, he is two years into his first chief executive job, with the chance to show that his thought-out approach can really work.

So far, so good. Inbev announced sparkling interim figures for the first half of 2005, and is currently rolling out the Brazilian beer Brahma through its key markets, where it can join the group’s other global superstars Beck’s and Stella. And the potentially tricky relations between two groups of controlling family shareholders, Belgian and Brazilian, appear to be holding firm.

But don’t expect Brock to get over-excited about running the world’s biggest beer producer — Inbev takes about 14% of the global market compared with SAB Miller’s 13% and Anheuser-Busch’s 12%. Being the biggest, he says coolly, is only a partial advantage.

“As I often say, it’s not totally irrelevant but it’s broadly irrelevant. What’s important is the position we have in any given market, and what we are targeting is the No1 or No2 position in every big market round the world.”

On that criterion, he is not doing too badly either. Inbev’s premium trio — Stella, Beck’s and Brahma — and a host of regional brands have pushed the company into top-two slots in 21 markets round the world.

Next Inbev wants to outstrip its rivals for profitability — the American giant Anheuser-Busch holds that crown. Brock is promising a 30% profit margin by 2007. The figures show he is on course. “You will have to ask Anheuser how it is doing,” he smiles, “but the American market is not a great place to be at the moment, unless you are at the premium end.”

Polite but rarely effusive, Brock, 57, exudes rational logic. When I ask what he found when he joined Interbrew in 2003, before the merger, he makes a small noise of appreciation — as if to say, “Good point” — and launches forth.

“It was fascinating, good brands, great people but it had fallen true to its previous description, ‘the world’s local brewer’ — we don’t use that tagline any more. It was appropriate at the time because it had grown from No17 to No3 in the world through a series of acquisitions. But it was not really focusing on global strategies, resource allocation, the co-ordination of marketing programmes, and global ways of making decisions. It was left up to local businesses to do their own thing.”

That was why Brock, with 20 years at Cadbury Schweppes and 13 before that at Procter & Gamble, was hired. He came with a wealth of experience as a global organiser — though not, interestingly, as a marketer. He has always left that to others.

Former colleagues say he made a good switch. “John is goal-orientated, he likes huge challenges and he knows how to make complex messages simple,” says Bob Stack, Cadbury Schweppes’s head of human resources. “He also has real knowledge of the international beverage industry from Cadbury’s soft-drinks side.”

His timing was good too. Interbrew was crying out for his kind of globalising expertise — easy improvements could be made from re-organising its growing collection of local outfits. And the top slot at Cadbury Schweppes, taken by fellow American Todd Stitzer, was not going to be his.

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