Clara Furse and the board of the London Stock Exchange have until the end of January to save the independence of the 300-year-old London Stock Exchange after American raider, Nasdaq, formally posted its £2.9 billion offer to shareholders.

January 27 is the last date for the New York exchange to make its final bid above the current £12.43 offer. Leading commentators in the City have expressed alarm over the possibility of losing London’s driving institution.

Nasdaq’s Chief Executive, Bob Greifeld, commented : “We continue to believe that our offer of 1243p represents a full and fair value for LSE shareholders taking into account the new competitive threats that the LSE will face in 2007 and beyond.”

In what was seen as fighting talk, he claimed Nasdaq would take control of the LSE if it buys a 50pc stake plus one share. They already own just under 29pc of LSE shares.

The Daily Mail reports : “Until today Nasdaq, as is common in most bids, had been aiming for 90 per cent acceptances, the level at which a bidder can force the remaining shareholders to sell out. Having a mere 51 per cent control of the LSE would considerably hamper what changes Nasdaq could bring to London. The offer document is also unusual in that it makes no great attack on the current management of the Stock Exchange.”

Greifeld is said to believe the LSE will face major competition from both Project Turquoise, a pan-European trading system being set up by seven of the world’s top investment banks, and from other low-cost alternatives.

Nasdaq has borrowed $5.1 billion (£2.6 billion) and will issue $775 million of preference shares to fund the operation.