KKR is often regarded as the grand-daddy of the buyout. It “starred” in bestseller Barbarians at the Gate, the story of its record $25bn buyout of RJR Nabisco in junk-bond and debt-financing-fuelled 1988. After maintaining a low profile for the best part of a decade, a newly active KKR’s advisers in Europe now include Sir John Bond, former group chairman of HSBC and now chairman of Vodafone, and businessman and friend of the UK’s Labour government, Lord Hollick. One recent appointments has raised a few eyebrows, however.

In January, KKR tapped Willy Strothotte, chairman of Glencore International (a commodity trader set up by one-time international fugitive and recipient of presidential pardon, Marc Rich), to serve on its board. Glencore is a privately held company with revenues estimated to have stood at €54.5bn in 2005 and a reputation for opaque oil trading.

Another person with a bulging contacts book is Peter Peterson, founding partner and now senior chairman of Blackstone. A former commerce secretary under Richard Nixon and chairman and CEO of Lehmann Brothers, he is also chairman of the Council on Foreign Relations (CFR; Henry Kravis, co-founder of KKR, and David Rubenstein, co-founder and managing partner of Carlyle, are also on its board). The Middle East connections of the CFR speak for themselves.

In the UK, official pressure on the private equity industry began last November when the Financial Services Authority expressed a number of concerns about the industry, including transparency. A working group under City stalwart Sir David Walker will report on the industry in the autumn. Spokesmen from the industry’s representative body, the British Venture Capital Association, have been heard repeating the line “We are transparent to our investors” in answer to the transparency question, particularly during the Boots takeover.

This begs the question: who are the investors? In one obvious sense, it simply doesn’t matter. Investments are investments, and money goes round in global circles. When the Russians want to buy British Gas, however, they are blocked from doing so.

Many of the current targets of private equity buyouts fall into the “strategic industry” category. By buying some of the biggest employers in a country, private equity firms and their investors attain political and economic ammunition to use in the game of nations.

Of course, if there is to be a public debate on the subject, it could be argued that Middle East investors are a more politically acceptable alternative to those from other blocs with a healthy trade surplus and large dollar reserves – Russia, say, or China. Indeed, there’s an even stronger case for arguing that the private equity boom is a fine and respectable place for monetary surpluses to go into. For a public scared by terrorism and in thrall to conspiracy theories, however, the continued secrecy of the industry will only serve to fuel suspicion.