The Margin's top corporate source tells the following tale. A managing director wanted advice on a major merger and, in particular, what his company's £2 million profit and the other company's £2 million would add up to.

He first went to the company economist. The economist said that taking into account recent growth trends, running the data through his econometric model, and bearing in mind the various externalities both positive and negative the answer could on the one hand be £3 million and on the other, £5 million.

Exasperated, the chief executive turned to the corporate lawyer. He said that he would have to take into account any mitigating circumstances and would need full disclosure to give a definitive view, but in advance of a final judgment the answer would probably be between £3.8 million and £4.2 million.

The MD was sure the accountant would give a straight answer. What would £2 million and £2 million make, he asked the bean-counter. The accountant leaned forward and replied: "Had you a figure in mind yourself?"