At the Chelsea Flower Show last Monday, I saw a former British prime minister talking to a former newspaper editor. The ex-prime minister was smiling broadly and expressing delight at the chance meeting. Yet about five minutes earlier he'd been overheard saying something disparaging about the ex-editor and trying to duck behind an oversized flower pot to avoid having a conversation.

What does this say about the politician? That he's a duplicitous weasel? Or that he has the polite charm that we require of the most successful people?

Last week I heard Dorothy Rowe, the Australian psychologist, talking on the radio about her new book Why We Lie. Even very small white lies, she argued, are motivated by a fear of damaging our idea of ourselves as people and will catch us in the end.

Better liars

This is far too deep for me. Lying is surely caused as much by pragmatism as fear. In my experience, it can be jolly useful. And tests have shown that in fact it doesn't always catch up with you.In the latest issue of the Harvard Business Review is an article stating that powerful people are better liars. Researchers from Columbia Business School asked bosses and staff to steal a $100 note and then convince someone that they hadn't taken it — a trick that bosses could pull off far more successfully than their employees.

Earlier this month, another study was published by psychologists at the University of Toronto showing that children who start lying by the age of two are more likely to be successful when they grow up. Lying is an important developmental stage: it means you can hold the truth at the back of your mind while saying something else at the same time.Together, these two surveys paint a scary picture. The cleverest are propelled to the top on a wave of lies, and once in power are compelled to lie even more.

I don't think it proves this at all. There's extreme lying, which is always bad. But there's also modest lying that's not bad; indeed it's absolutely essential to get through a day in the office. What is needed, however, is more than just being economical with the truth; it's being sophisticated with it. People who thrive, like the ex-prime minister, have reached the further developmental stage of knowing just how far they can tell different stories to different people, while still (one hopes) holding on to some core of honesty. It's knowing which lies harm and which help. Only the very stupid, the very rude and the very young never lie in this way.

Last week I bumped into someone who I'd invited to my book launch, but who hadn't come. Sorry not to have seen you, I said. "I get asked to a lot of parties. I thought I could give a miss to yours," she explained. Such compulsive truth-tellers don't last in organisations Offices are glued together with lies.

We pretend to like people we work with. We must pretend to be satisfied with our jobs. We must pretend to think our company is better than the competition. By accepting a place in any hierarchy, you are bending yourself out of shape.

So when asked by an anxious editor: ‘How are you getting along with your column?' I say: "Nearly done. It'll be with you by six."The truth is the column is barely begun. The next bit is true. Deadlines must be met. I'm proud of my lies. Proud of my ability to adjust my behaviour according to the circumstances, I hope I've passed on the gift to my children.

— Financial Times.