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.