Following Lord Browne's candid memoir, the spotlight has been thrown again on whether the privacy of senior business figures can ever be fully protected

I was certain that if people in BP had known I was gay, it would have been the end of my career," writes Lord Browne in his new memoir Beyond Business. The book charts his 41 years with the oil group, 12 of them as chief executive, and the successes that earned him the soubriquet "Britain's most admired business leader" for several years.

He is also frank about some of his failures, but never more so than over the lie he told to BP's lawyers about his relationship with his former boyfriend Jeff Chevalier. "I was ashamed and embarrassed... I just could not bring myself to tell the truth," he writes.

It is ironic that while people would probably have been more accepting of his private life than he feared, it was lying about it that hastened his departure.

All of which raises the question of whether the private lives of business leaders need to be unimpeachable. After all, to err is human, and most people who bay for the blood of those in the public eye must surely be hypocrites. Provided their "on-pitch" performance remains unaffected, then surely we shouldn't care what they do behind the privacy of their own front door?

Well, yes, actually, we should. The "celebritisation" of business means that leaders are not faceless custodians of corporate assets, but role models who must accept their responsibilities as good corporate citizens. That means behaving with integrity in both their public and personal lives because, with increasing transparency and the swift dissemination of information afforded by the internet, "private lives" are not really private at all.

That may seem hard, but it is one of the responsibilities that go hand-in-hand with what many businesspeople see as their rights-not least high pay and a propensity to make decisions that seem to benefit certain groups of stakeholders at the expense of others.

Business leaders who lie or who betray personal relationships should not be surprised to lose trust: they may feel they can compartmentalise different aspects of their lives, but employees, investors and customers understandably fear that a moral failing manifested in one area could easily translate to another.

Unfortunately, the nature of publicly listed corporations can turn well-intentioned individuals into, if not quite monsters, then soulless functionaries in a morally corrupt system that sacrifices long-term sustainability on the altar of short-term targets.

Roger Steare, professor of organisational ethics and corporate philosopher in residence at Cass Business School, says that just five to 10 per cent of business leaders take their personal responsibilities seriously, five to 10 per cent he describes as "functioning sociopaths", and the vast majority don't think about personal ethics much at all.

For the system to change we need adjustments to company law, and we must inculcate a more ethical and values—led approach to business education in our schools, universities and business schools. But we also need to be far more careful how we choose the people we groom for leadership, and help them guard against the dark-side behaviours that are an inevitable corollary of the strengths that fit them for leadership, but which manifest themselves either when they are under pressure or when they reach the point where their success makes them feel invincible.

In Jim Collins's 2001 book, Good to Great, he lists the qualities of the people who run the handful of companies that he identified as great. The key attribute of what Collins calls Level 5 leaders is a blend of "extreme personal humility with intense professional will". He writes: "Level 5 leaders channel their ego needs away from themselves and into the larger goal of building a great company. It's not that Level 5 leaders have no ego or self-interest. They are incredibly ambitious, but their ambition is first and foremost for the institution, not themselves."

The concept of ethical leadership is gaining currency. Ethical leaders will make decisions based on their social and environmental, as well as financial, impact, and implicit in the ability to do that will be strong moral fibre.

Steare has devised a test to measure moral values, and hopes to persuade political party leaders to take it before the election. It would be interesting to see how many business leaders would subject themselves to similar scrutiny.