The battle for the London Stock Exchange gathered steam yesterday as the Deutsche Borse called on its allies in Madrid and Milan to back a possible "white knight" offer for the UK bourse.

Mr Rolf Breuer, chairman of the Deutsche Borse supervisory board, expected the plans to merge London and Frankfurt to succeed despite the hostile £847 million sterling (€1.4 billion) bid made for the LSE by OM Group of Sweden on Tuesday.

But several exchanges could join in defending the plans to form iX. Deutsche Borse is sticking to its timetable for a shareholder vote on iX despite the LSE's decision to postpone its vote.

Shares in the LSE, which are traded on a matched-bargain basis, rose yesterday to £28.50. OM has offered LSE shareholders £28.20 per share, a premium over the valuation of the exchange based on the share's closing price of £23.50 last Friday. The LSE board has rejected the offer.