Nomura has privately made clear that its offer would depend on Mr Bonham staying at the helm, alongside John Devaney, chief executive of Eastern Group, the regional electricity company owned by Energy Group.
If Mr Bonham and Mr Devaney recommend a Nomura bid, it could see senior Energy Group executives emerging with similar windfalls to those seen in other recent Nomura deals. Late last year the Japanese group sold Angel Trains Contracts, the rail leasing company, netting pounds 15m for its managing director, John Prideaux.
Nomura yesterday confirmed that it was in talks with Energy Group. The bank, which is expected to decide whether to bid by the end of next week, also disclosed that it has built up a 2.2 per cent stake in the company, worth pounds 85m. However City sources doubted whether a financial offer by Nomura would clear UK regulators.
Two US utilities are also considering launching bids, PacifiCorp and Texas Utilities.