Banks Enabled Leverage in Madoff Scheme

What is worse than the lack of due diligence performed by the fund of funds that invested nearly all of their capital in the Madoff funds?  The banks that allowed the "feeder" funds to leverage their bets on the Madoff.  According to the Financial Times, HSBC, RBS, Nomura and BNP Paribas lent money to the fund of funds so they could lever up their investments in Madoff.  A simple ponzi scheme after all, is really nothing compared to a leveraged ponzi scheme.  These loans were ultra-safe, of course, because they were secured by "assets."  RBS (now mostly government-owned) and HSBC were extremely conservative by only allowing two-times leverage on the imaginary assets in the feeder funds.  Nomura, on the other hand, in an attempt to shirk its image as a conservative Japanese bank, allowed thrice the leverage on the underlying imaginary assets.  One would think that the banks would try to verify that some assets actually existed before going crazy with the lending.  But one would be wrong.  Little, if any due diligence was performed.  Much like the fund of funds, they were not hesitant to collect their fees, just didn't really want to work to justify them.