I HAVE NO EXCUSE to offer. Particularly after they dropped such a big hint. I’ve read it twice. I’ve passed it by on my bookshelves dozens of times. At one time I’d even photocopied bits of it, given the copies to friends and left Post-it Notes on the pages I thought were particularly interesting. (My grandfather didn’t believe in scribbling in books. Not even his name. He lost thousands of volumes when the Nazis came, but still it’s a family thing — never write in books. The Post-it Note has been a real boon.) Yet despite all this, I missed it completely.

Still, though it took for ever, the penny has now dropped. And I have it now on my desk in front of me — the manual that explains what David Cameron is doing to the Tory party and how they should react to the disappointing result in Bromley and Chislehurst.

Let me tell you about the big hint they dropped. A few months ago the Conservatives published a statement of principles, which members are to be asked to vote on. The contents were familiar to anyone following Mr Cameron’s pronouncements (“It is our moral obligation to make poverty history” and so on), but the title was unfamiliar and slightly odd. Built to Last they called it, and these words now frequently appear behind Mr Cameron when he makes speeches.

At about the same time as the Tory statement was being issued, Random House was publishing a tenth anniversary edition of a cult business book on the successful habits of visionary companies. And its name? Built to Last. I understand from advisers to Mr Cameron, once it had occurred to me to ask them, that the shared title is not a coincidence.

At the end of the 1980s two American academics, Jim Collins and Jerry Porras, began to research what they termed “enduring great companies”, ones that had been successful for decades — companies such as Disney, Sony, 3M (without whom no Post-it note), Marriott and Hewlett-Packard. The authors’ aim was to identify the characteristics that these companies all share and that distinguish them from others. The list they came up with reads like Cameron’s blueprint for Tory modernisation.

At the heart of the book is this assertion: visionary companies are about “more than profits”. Profits are vital, but “they are not the point of life”. Instead, companies adhere to core values and purpose, a core ideology that gives the company its character and its reason to be. Around the maintenance of these values, a fanatically disciplined, cult-like organisation is built. Everything can change, everything must change, but not the core ideology.

However, Collins and Porras argue that the biggest mistake you can make is to fail to distinguish between core ideology and non-core practices. Take IBM. The “three basic beliefs”, as defined by the founding fathers of that company, are “to give full consideration to the individual employee, spend a lot of time making customers happy, and go the last mile to do things right”. As the authors observe: “Nowhere do we see anything about white shirts, blue suits, specific policies, specific procedures, organisation hierarchies, mainframe computers — or computers at all for that matter”.

Or take the Disney Corporation. Part of its core values and purpose was “to bring happiness to millions” and to promote “wholesome American values”. It did not define itself as a film company just for children. Good thing too, or we wouldn’t have had Touchstone Pictures. Indeed, it didn’t define itself as a film company at all. Good thing too, or we wouldn’t have had Disneyland.

So “preserve the core/stimulate progress” is the advice of the Built to Last authors. Change is relentless; it is ruthless. Ideology is something you discover rather than establish and it is deep within you. They suggest that every time you think of something you might wish to do (cut taxes, say, or issue education vouchers) you ask yourself the question “Why?”. Five or more iterations of “Why?” and you might begin to hit your core.

The authors also add this: “The role of core ideology is to guide and inspire, not to differentiate.” As they put it: “It’s entirely possible that two companies can have the same core values or purpose. Many companies could have the purpose ‘to make technical contributions’, but few live it as passionately as Hewlett-Packard.”

Visionary companies are also audacious. They adopt what Collins and Porras call Big Hairy Audacious Goals. Boeing bet the farm on a move into the commercial jet market, Sony set itself the task of creating a pocket transistor radio, Merck decided that it was going to be the pre-eminent drug maker worldwide. These were not chosen at random, they flowed from the core purpose.

The Cameron view is that the Conservative Party is an enduring visionary company fallen on hard times. For years it has been confusing its core purpose with its operating practices, muddling up specific policies (for instance privatisation) with basic beliefs (improving the quality of life for individuals), allowing day-to-day conventions (say, letting constituency parties select who they like) get in the way of core purpose (say, winning elections). In the confusion the Conservative Party lost the cult-like discipline that was once associated with it and the will to pursue Big Hairy Audacious Goals evaporated.

Built to Last makes one other thing clear — Mr Cameron has only scratched the surface, and he knows it. Visionary companies take years to mature. When William Hewlett and Dave Packard got together, it took them years before they could even decide what to make. A long process of discovery, experimentation and disciplined action lies ahead for the Tories.

The Bromley and Chislehurst by-election will have disappointed those hoping for a swift recovery. But those who want to see a return to the Tory party’s glory days should be grateful. Foolish Tories might think the results show that things have gone too far. The smart ones will understand that change has only just begun.

Times Recommends

• Treat Africans as part of the human jigsaw
• Too bitter a pill for me to swallow
• This Bill is a panic measure in a tarnished age