Sometimes you've just got to pretend to get on with the people you detest the most

HOW To Work With Your Best Foe: A User's Guide is shortly to be compiled by Barack Obama as he deploys his dearest frenemy, Hillary Clinton, as the US Secretary of State.

The Obama-Clinton competition for the Democrat nomination was a study in the darkest art of politics – how to try to kill off someone on your own side. She said (I translate roughly): "If the phone goes at 3am and there's (another) world crisis, he has no more idea of what to do than my aunt Betty."

He said in a debate: "You're likeable enough" – one of the best back-handed compliments on record – meaning, "Everyone hates you apart from your cronies".

Now, however, it's all kiss and make up (emphasis on the make-up), just as Peter Mandelson now advises our Prime Minister Gordon Brown, a man he once observed could be very helpful to the New Labour project "if only he'd join it".

It isn't really so different for the rest of the working population: the fact is that enemies are a part of corporate life.

The first dilemma that throws us is whether you should ever openly acknowledge it. Or, on the advice of singer Lily Allen, take the ultimate revenge of sweet indifference: "At first, I felt bad for a while/But then I just smile/I go ahead and smile."

A quick straw poll of how to deal with the desk enemy elicits a barrage of stories about office feuds.

One colleague of mine had a rival who used to spread his body halfway across the desk, which he did simply to prevent her sitting opposite the boss at important meetings. He also greeted the news of her resignation with a beaming: "Congratulations."

A sure sign of deep enmity is that people who dislike you exaggerate their responses to you: extreme courtesy, for instance, often hides a boundless capacity for enmity. I asked one fashion-industry executive how she managed to stay so serene when she heard about the elevation of someone she loathed. She cited the old proverb, "Stand on the bank of the river long enough and the bodies of all your enemies will float by". So true – but by the time that happens, you're probably too old (and wise) to care or to do anything about it.

For a lesson in how to handle interpersonal conflict with style, you should watch Meryl Streep doling out a marvellously glacial non-embrace to her French magazine-editor rival in The Devil Wears Prada – and the milli-second glance of triumph that accompanies it. Hillary Clinton's face on being hugged by Obama also conveyed her desire to get it over with: her smile was too stretched, her eyes too wide.

The alternative is that you could always just say what you think, of course.

"Why aren't you going to so-and-so's drinks party?" I recently asked one acquaintance. "Because I don't like her," came the blunt reply. The downside of adopting this approach: social life in the city would quickly grind to a halt.