Once upon a time, it was presumed that the actions of central bankers controlled behaviour in the risky lending world. For if central banks jacked up rates, the argument went, the cost of borrowing would rise - making it harder for highly leveraged groups, such as buy-out funds, to snap up deals.

Now, however, this argument is looking a touch quaint. In the last couple of years, Western central banks have indeed been raising rates. Meanwhile, investors have had to contend with minor matters such as surging oil prices, Middle East turmoil, and now subprime woes. Yet, the credit party has continued, seemingly oblivious - triggering a buy-out frenzy.