The barbarians are again at the gates. The announcement this week of the largest ever private equity buy-out of a public company - the $45bn (£22.9bn) takeover of TXU, one of the largest utilities in the US, by Kohlberg Kravis Roberts and Texas Pacific Group - confirms the trend.

To its defenders, private equity makes companies more efficient. To its attackers, its practitioners are financial manipulators and asset-strippers.