The London Stock Exchange has increased the pressure on Euronext and Deutsche Börse by raising its offer for Liffe, the derivatives exchange, to over £17 a share, according to sources close to the exchanges.

The price of the indicative offer is nearly 70% higher than the level at which shares in Liffe were trading before speculation about an imminent bidding battle started in the summer. The offer values Liffe at around £550m (€877m), and is well above the minimum £16 a share demanded by Liffe for serious bidders.