If shaking hands with tyrants seems bad, what about their corporate friends?

This week, there has been a fuss about Jack Straw accidentally shaking the hand of the Zimbabwean tyrant Robert Mugabe. Yet BAE Systems - the people who sold him the tools for his tyranny - have been handing out glossy brochures at the Labour Party conference all week without a single angry glance or a single protesting article. And that's only one of many long, lingering trails of blood to run through the Brighton conference centre.

This week, there has been a fuss about Jack Straw accidentally shaking the hand of the Zimbabwean tyrant Robert Mugabe. Yet BAE Systems - the people who sold him the tools for his tyranny - have been handing out glossy brochures at the Labour Party conference all week without a single angry glance or a single protesting article. And that's only one of many long, lingering trails of blood to run through the Brighton conference centre.

Every year, the friends and accomplices of some of the worst human rights abusers in the world mill around our party conferences, smiling at delegates and trying sweetly to coerce ministers into serving their interests.

We do not usually notice these people because they are treated as private companies like any other. They pay for lavish conference exhibitions and exude respectability. But BAE Systems are a gang of arms dealers who have equipped - among others - the House of Saud and the staggeringly vicious Indonesian government. It is a matter of record that these weapons have been used to murder innocent people.

And BAE Systems look like Amnesty International compared to some of the corporations that are embraced by our most senior politicians. The centres of British power are crawling with paid representatives of corporations that directly profit from slave labour.

The oil company Unocal has a history of collaborating with murderers, from the Taliban to the horde of butchers who have hijacked state power in Burma (death toll: half a million and rising). The corporation is raking in cash from a pipeline built and maintained by Burmese slaves. The workers have no ability to leave and no rights whatsoever. The wages are 23 pence a day. If they protest about this, they face rape, torture and death.

A crucial test case in Los Angeles at the moment is exposing Unocal's behaviour in Burma during the 1990s. Refugees who managed to flee to America testify that thousands of residents of their villages were forced at gunpoint to work on Unocal's pipeline. This is the reality of corporate "investment" in tyrannies.

How do our politicians and press respond to this? We do not condemn; we welcome these companies into the Palace of Westminster. Their lobbyists breakfast, lunch and dine our elected representatives every day.

And they get results: they get handed huge sums of your tax money, too. Look at BP. They are key players in building a massive pipeline through the Caucasus. You might think that, as a firm that constantly boasts about being "good corporate citizens", they would take care to respect the local environmental and labour laws.

In fact, they have demanded an exemption from all of Turkey's environmental and human rights protections formulated by the country's sophisticated democratic process. In the event of oil spills and deaths caused by their project, they have ensured they will not have to pay compensation. And the British government is contributing ?85m towards the project - just in case BP's profits dip.

Well, you might ask, what did you expect? Big business will pursue profit at the expense of human rights and the environment - and snatch as much from the public purse as they can. What revelations will come in my next column - Santa Claus isn't real?

But our government's policy towards corporations is based on precisely the naive assumption that these corporations can be coaxed into behaving decently just by asking nicely. Ministers have claimed for seven years that they are trying to civilise corporations by encouraging them to voluntarily adopt something called "Corporate Social Responsibility" (CSR). Put simply, this means they are trying to get massive corporations to agree to change their behaviour substantially without any legal requirement to do so.

Corporate Social Responsibility is a dud. This week, Friends of the Earth presented their annual Xpose Awards at Labour Party conference. These gongs are awarded to the most blatant hypocrisies and deceptions to lie behind corporations' glossy CSR brochures - and there are so many that the CSR enterprise is exposed as a farce.

The most significant Xpose award went to the United Nations' Global Compact for Multinationals. The UN tried last year - with noble intent - to get the world's leading multinationals to sign up to 10 basic principles, including respect for human rights and the environment. The companies - including Nike and Starbucks - eagerly agreed, on the condition that the compact promises not to "police, enforce or measure the behaviour of companies". No need for any of that malarkey. Oh no - we can all trust, instead, the "enlightened self-interest" of profit-driven companies.

This exposes the hole at the core of CSR. Corporations are structured to seek profit, full stop. Because they operate at the level of the globe, they need to be bound by global laws. Everything else is waffle. This is why supranational institutions such as the European Union are so important. Pretending that companies will magically change and adopt real CSR is a Blairite delusion that only staves off the day when proper, effective international regulation is introduced.

We find it quite easy to recognise state tyrannies like Mugabe's or North Korea's. It is much harder for us to recognise the capacity of corporations to act as - to borrow a phrase from Noam Chomsky - private tyrannies. It might sound strange at first to say that a company could ever be tyrannical. But a tyranny is any group that has seized power without having a legitimate claim on it. Sometimes they seize state power, à la Saddam. But sometimes they co-operate with state power - like Unocal - and sometimes they simply seize power in a vacuum, as employees of the multinational Coke has been accused of doing in Colombia by employing paramilitary "security forces".

What right does Unocal have to profit from the slavery of Burmese people? What right does Coke have to wield such power over Colombian people? They are not accountable to the people of Burma or Colombia in any way.

Don't get me wrong - this is not an anti-capitalist view, and I don't buy the entire Chomskyite package. We need companies. Markets are an essential part of any economy. But they are only part of it - they need to be counterbalanced by strong regulations, democratic and environmental protections, and trade unions.

In much of the world, this has been forgotten. Corporations have become the dominant cultural institution and, as a result, some - like Unocal - have become human rights-abusing monsters. Even in advanced democracies, they are having an increasingly corrosive effect - just look at the corporate buy-out of American democracy. Corporations need to be put back into a social democratic cage, and fast. Shaking Mugabe's hand was bad - but inviting private tyrannies into the heart of the Labour Party conference is worse.

j.hari@independent.co.uk