A leader without a critical friend to tell them where they are going wrong is exposed, often without knowing it

Watching yet another repeat of the film Mrs Brown I am struck by parallels to some of the issues with which our senior leaders struggle.

Queen Victoria's problem, possibly only dimly perceived by her, was the dearth of people who were in her court because they liked and admired her. Most were there for personal advancement. At the turning point of the story, her gillie, John Brown, stubbornly waits daily with a horse for her to ride out, ignoring the exaggerated grief to which everyone else has been pandering. His indifference to power politics and his willingness to speak truth to her is what gives him his influence, even while she is crossly announcing that 'No-one is more wise than the Queen'.

A leader without a critical friend is exposed, often without knowing it. The richer and more powerful they are, the more they can afford to hire people who soothe, nanny, flatter and keep the rest of the world at bay. They attract people who bask in the glow of celebrity. Paul Burrell, butler to the late Princess of Wales, is the perfect example.

In this protected bubble, the leader's all-too-human faults can grow unchecked. Such people often come to believe their own publicity, forgetting that their magnetism lies in their assumed power, not in their sexual attractiveness or intrinsic likeability.

One of the most dramatic examples in commercial life is Sir Richard Greenbury, who was chief executive of Marks & Spencer at the time of its near collapse in the late-1990s. As unflinchingly described in Judi Bevan's book on the subject, the people around him feared the bulging-eyed rages that could be provoked by any breath of bad news, and indulged his beliefs that the company could cut costs, reduce quality and raise prices without customers noticing. Behind his back, his directors were squabbling about who would succeed him.

In the same vein, the Tory party is still suffering from the Thatcher legacy where, again, an egotistical leader had no-one who dared confront her openly over a disastrous policy.

The role of critical friend demands grown-up self-confidence, maturity, courage and indifference to formal power. Such people have to see and like the real person beneath the braggadocio. They have to be able to walk away fearlessly, but not in a huff, if it gets too much. As the leader you have to acknowledge that you need this person, annoying and difficult to hear though their messages might often be. You have to be able to see that their judgement is often right, even when it contradicts what everyone else is telling you.

It also seems to be the case that some successful leaders are able to sustain the fiction of being 'nice' or 'wise' only because they have a John Brown figure in their lives. Tony Blair maintained his Mr Ordinary Guy image because he had Alastair Campbell as Mr Nasty, who was able to utter the tough truths that the inevitable toadies were afraid to say. And of course, Bill had Hillary.