A potential £1.9bn (€2.8bn) joint bid from US giant Constellation Energy and hedge fund Perry Capital for the UK's Drax Group is threatening to derail the power station's plan for a London stock market listing in December.

Lazard is advising Constellation Energy, the largest wholesale energy trader in the US, and Perry Capital on their cash offer for Drax and Credit Suisse First Boston is arranging the debt financing. Two of Constellation's traders moved to CSFB at the end of last year.