This has been a record year for world stock markets with IPOs raising £116 billion ($227bn), according to Ernst & Young.

The Hong Kong Stock Exchange did best, grabbing 17pc of the total. But the London Stock Exchange came a close second, with 15pc, ahead of the New York exchange on 11pc, Euronext on 8pc, and Nasdaq, at a lowly 6pc.

Much of the bonanza has come from Russian and Chinese companies seeking havens in lightly-regulated financial centres. The LSE has scored heavily over the American outfits because of the negative effect of the Sarbanes-Oxley legislation.

Nasdaq has made a new offer valued at £2.7 billion ($5.13bn) for the London Stock Exchange.

The LSE board has rejected the bid, claiming it undervalues the buoyant stock market, which has posted record trades and earnings in recent reports.

Nasdaq already owns more than 25pc of LSE shares, giving it a powerful advantage in the current round of consolidation deals. With the New York Stock Exchange well on its way to takeover Euronext, Nasdaq sees a liaison with the LSE as strategically crucial in its battle for business with its close NYC neighbour.

Shares in the LSE have traded briskly since the offer was made. The BBC calculates that if Nasdaq bought them all, they would have a 50pc holding in the company. That’s unlikely to be the case though.

With a proposed softening of America’s draconian Sarbanes-Oxley rules and a new bill protecting the LSE from foreign regulation from the Treasury, the major obstacles to a merger seem to be melting away.

Clara Furse and her board may have other tricks up their sleeves, not least a tieup with an exchange in the Far East — Tokyo was mentioned recently.

It’s still all to play for.

The Business Editor of the BBC last night broke the news that at least half a dozen American investment banks are in the process of setting up a giant European stock exchange to challenge the rest.

The group includes Goldman Sachs, Merril Lynch and other “household” names. They already have successful platforms for buying and selling shares, so by combining their strength and lowering prices they will pose a formidable threat to the mainstream exchanges, especially the LSE and the proposed NYSE-Euronext conglomerate.

The BBC’s Robert Peston thought the threat may make the presumed bid for the LSE by Nasdaq more likely to succeed.

With the taming of the worst features of America’s Sarbanes-Oxley regulations in prospect, the walls that have hitherto shielded an independent LSE seem to be crumbling.

In a speech to the British Bankers’ Association, Treasury minister Ed Balls announced that he will introduce legislation before Christmas to “safeguard the light touch and proportionate regulatory regime that has made London a magnet for international business”. He said the new law is “not intended to make overseas ownership of UK exchanges any easier or more difficult than it is at the moment”.

He had previously planned to add these clauses onto the slower-moving Companies Bill legislation. Balls also said he is determined to maintain “sensible and light touch” regulation of the financial sector at global and EU level.

The new regime will mean that any bidder for the LSE will face a lengthy regulatory process before a takeover can go ahead.

It has been suggested that Nasdaq has held a series of high-level, confidential meetings with the Treasury, and feels assured it would eventually secure the go-ahead.