In a statement, the LSE said: "The approach is at an early stage and therefore does not require a response at this point. Discussions with Deutsche Börse and Euronext will continue."

No financial details were forthcoming, although Euronext is expected to trump Deutsche Börse's 530 pence a share offer of 11 December. The LSE rejected the German exchange's initial offer but has been continuing talks. Deutsche Börse chief Werner Seifert has been sweetening the deal with talk of senior positions for LSE management in the merged entity and a prominent role for London in the administration and running of the market.

Shares in the LSE have continued to rise, adding nineteen pence in early morning trade to stand at 575 pence.