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.