Euronext has announced that it supports a proposal to merge its stock exchanges with Deutsche Borse and Borsa Italiana, as long as it is part of its merger with the New York Stock Exchange.

The intriguing possibility now opens up of an even bigger transatlantic giant emerging to challenge the London Stock Exchange.

With Nasdaq in talks with the hedge funds which own 30pc of LSE shares and a figure of 1300p being bandied about as the cost of buying out these shares, it’s beginning to look like two great pan-Atlantic exchanges may emerge over the next 12 months.

Unless, that is, Clara Furse can find a white knight to save the old LSE.

A tie-up between the London Stock Exchange and Icap, the world’s largest inter-dealer broker, has been discussed during the summer, it has emerged.

Icap is expected to confirm today that talks have taken place. The main sticking point seems to be the current share price of the LSE, which, at more than £12 ($22.56), has all but doubled this year.

A merger would create a formidable all-British heavyweight valued at £6 billion ($11.28bn), with a strong derivatives base. It would, at a stroke, make up for the strategic defeat of losing Liffe to Euronext.

However, the complementary nature of the parties means that cost savings would be hard to find. Whereas Nasdaq might justify the high price of a bid (£12.43 is the floor price it must pay in the near term) by savings derived from rationalization, Icap would see a dilution in value after any deal.

Clara Furse, the LSE chief executive, has a lot of balls in the air as the autumn season gets underway. Buying the Scandinavian exchange OMX, is one option; various possibilities involving private-equity outfits also beckon, plus the tempting prize of Icap.

Over-arching all, however, is the American Nasdaq, which, with 25.3pc stake and a clear field of play from next Monday, remains the one to be beaten.

At last Clara Furse and the board of the London Stock Exchange are waking up to the threat of Nasdaq and Sarbanes-Oxley regulation. It seems they are looking for a “white knight” among private equity firms.

Meanwhile, the prospect of a direct takeover of OMX, the Scandinavian and Baltic exchange operator and former bidder for the LSE, has been around for a while and seemed dormant. But as the LSE hummed and hah’d, fiery Nasdaq has let it be known that it too may bid for the company. Mysterious.

Alex Brummer, the UK Mail’s City Editor, opines : “Under the stewardship of Clara Furse we have an LSE which has enriched investors but lost global standing.”

Now we are being fed the notion that an almost £3 billion ($5.5bn) management buyout, led by Clara Furse herself and backed by private equity, would keep the aspidistra British flag flying over London soil.

Well, it’s better than nothing. Let’s see some action though before October 2 when Nasdaq is handed the golden arrow. And a deal with OMX would help protect the LSE from the new Euro-American conglomerate even now thinking ahead to its demise.

Euronext, the Pan-Continental stock exchange, is said to be pressing on with its plans to merge with the New York Stock Exchange. Final clearance should be obtained by January.

Suggestions that Euronext may walk away from the NYSE deal in favour of a tie-up with Deutsche Borse and Borsa Italiana, have been scotched by a number of sources.

Meanwhile, the London Stock Exchange waits on the next move by Nasdaq, which can now launch a full bid for the LSE, if that’s its intention.