Earlier this week Hugh Freedberg, CEO of Euronext's London-based derivatives exchange Liffe, warned that a merger between Euronext and Deutsche Börse would see "an exodus of jobs" to Frankfurt.

Freedberg claimed that up to 5000 City of London jobs could be lost if the Deutsche Börse proposal goes through because the derivatives business would be relocated to Frankfurt.

However the German exchange has denied that it intends to relocate Liffe to Frankfurt and says it is committed to maintaining a strong presence London.

But according to a report by UK newspaper The Independent, both Apcims and Liba have urged London firms to reject the Deutsche Börse bid amid fears that Liffe could be closed down. Liba has also called for a full investigation by Europe's competition watchdogs into the bid.

"There needs to be a push to say this is wrong," Apcims' chief executive Angela Knight told the newspaper. "We fear the Deutsche Börse proposal will have the effect of shutting Liffe down. Who owns an exchange does not matter, but to reduce the number of derivatives exchanges would be wrong."

Alan Yarrow, Liba's chairman, said that this complex issue "can't be given sufficient attention in the very short period of time that the EC's stage-one inquiry is offering".

Euronext agreed a $10 billion - or EUR7.8 bn - takeover deal from Nyse in May, after rejecting a rival offer from Deutsche Börse. Euronext shareholders are due to vote on the proposed Nyse takeover in December.

But Deutsche Börse is intent on pursuing a merger with pan-European exchange and said earlier this month that it had signed a letter of intent with Italian stock exchange operator Borsa Italiana "aimed at creating a federal European exchange that includes Euronext".