Lehman Brothers’ top investment bankers in London have been offered large guaranteed cash bonuses by Nomura, the Japanese lender that this week bought the European and Asian operations of the bankrupt Wall Street bank.

Nomura has offered to pay Lehman investment bankers the equivalent of last year’s bonus, in cash, if they stay until the autumn of 2009. It has also promised that the 2009 bonus pool will be the same size as last year, though a proportion will be in the form of restricted stock.