The main vehicle for sorting out this and all of the other key decisions at ICI is the executive team, which comprises Sir Denys plus the eight executive directors on the ICI board. They devise general policy, set budgets, weigh the competing claims of the various ICI businesses for resources, and monitor progress.
In this context, though he does not use the analogy himself, he clearly sees himself as more of a John Major than a Margaret Thatcher - a team leader, very much primus inter pares rather than a dominant (or domineering) force. He relies heavily not just on the individual expertise of the other members of the executive team but on their collective wisdom.
He described the relationship neatly when he became chairman-designate in 1986. "When the chairman or the chief executive in the US says 'Roll over' then everybody unquestioningly rolls over, and if they fall out of bed he gets fired and if it's successful he gets rewarded monumentally.
"In our system, which is a pretty open participative system, when the chairman says 'Roll over' the other guys say 'Which way? Why? Shall we turn around?' So by the time we come to a conclusion it has been very well thrashed through. When we make a decision it is a decision of the executive team as a whole. It is not the decision of one man."
That sounds as though it might stifle individual initiative. In practice it does not. Sir Denys has plenty of scope for executive action and he can, if need be, move very fast.
Last summer's sale of ICI's 25% stake in Enterprise Oil is a case in point. Tactically speaking it was very much Sir Denys's show. The board had taken the strategic decision that it was time for ICI to get out of oil some time previously, but precisely how it should be done and when was problematic, particularly as a recession seemed to be looming on the horizon.
Then, on August 2, says Sir Denys, just as he was about to board a plane for Aberdeen, he heard about the Iraqi invasion of Kuwait. "I was immediately on the phone to Colin Short, who was about to become our finance director, and said 'Colin, there's a window here. We should move quickly.'"
They did. Within 12 days Short had sold the lot for "a very advantageous price", says Sir Denys.
He actually thinks that he and his senior colleagues began to discern the impending recession well before most other people, as early as mid-1989. By the turn of the year he had ordered a severe belt tightening which, he says, boiled down to the "four Cs" - cash, costs, capital and courage. Cash has to be kept tight (ICI's borrowings are down and its gearing modest), costs are being reined in, and constraints are being put on the sanctioning of future capital projects.
The courage, he says, is about taking difficult decisions. "Do you stay in a business or withdraw from it? Do you close sites? Do you lay people off? The courage is about that, but it's also about having a vision of the future and perhaps saying that against all these difficulties we're still going to support this business because we think its prospects are good, because at some stage you do come out of recession."
Sir Denys and the executive team will have a whole raft of difficult decisions to take over the next few months. He became convinced last August that the recession was going to be really rough, so he ordered a thorough reappraisal of ICI. A key question was whether the business strategies hammered out in 1980 when ICI embarked on a major change of direction, making it more international and much less dependent on bulk chemicals, were still valid.
The changes have been profound, he says. There has been a big move away from reliance on bulk chemicals and much more emphasis on "effect" chemicals (the higher value added products like pharmaceuticals). "We've increased the percentage of sales from high added value 'effect' businesses from 34% in 1980 to 56% today. At the same time we increased our penetration of important world markets. Consequently our dependence on the UK market reduced from 42% of chemical sales in 1980 to 22% in 1990, and sales in the Americas rose from 16% to 29% and in continental Europe from 19% to 26%."