For all the talk - and the substance - about London's rise as a global financial centre, the British have an Achilles' heel: the investment banks and brokers that dominate London are foreign.

The failed efforts by British banks such as SG Warburg during the 1980s and 1990s to expand internationallyare now a footnote to history.

Schroders and Warburg lacked the management skills and breadth of financial expertise of international banks and were swallowed up by them. Fair enough. London's strength after Big Bang was that it was an open and meritocratic trading place that recognised that it was better to let American, Swiss and German banks take charge.

Still, I sometimes feel a little wistful about the outcome. So forgive me a moment of patriotic pride at the unseemly scuffle that has broken out in the US treasuries market between Tullett Prebon and eSpeed, an electronic trading platform controlled by the US broker, Cantor Fitzgerald. It is the latest bout in a global contest that British financial services firms, for once, are winning.

Call it the revenge of the barrow boys. The old City of London was stereotypically split between the posh folk who ran the merchant banks and the Essex lads who worked on the floor of the London Stock Exchange or for market-makers and brokers. The latter did not literally push barrows around, but they were country cousins to those at London's meat, fish and produce markets who did.

When SG Warburg made its abortive effort to go global, its chief executive was Lord Cairns, otherwise known as Simon. When Barings collapsed in 1995 from the misdeeds of the barrow-boyish Nick Leeson in Singapore, it was led by Peter Baring, whose cousin is Lord Ashburton. Not to put too fine a point on it, the gentry made a hash of things.

A decade later, the barrow boys are restoring some British pre-eminence. The City firms that have become global institutions are the déclassé inter-dealer brokers.

That is about as tiny and humble as it gets. Yet they have evolved into the hubs of bond and derivatives markets around the world: they run electronic trading platforms such as Icap,rival to eSpeed in treasuries; they also trade a mind-boggling range of over-the-counter contracts, from energy and shipping derivatives to silver and palladium futures.

The British firms top the global league of inter-dealer brokers in terms of revenue, with Tradition, a French-owned group, and GFI Group and Cantor Fitzgerald/eSpeed of the US behind them.

If Tullett's $600 million (€441 million) hostile bid for eSpeed succeeds, which does not look particularly likely at the moment for reasons I will explain, they will even have sewn up electronic trading of treasuries.

The British firms were no doubt hungry: their domestic bond market was much smaller than the US ones, so they had to expand internationally.

But that was also true of merchant banks and stockbrokers in the 1990s and it did not do them much good.

The difference is the inter-dealer brokers have run their operations better and proved more adept at taking on foreigners. This is a tribute to the culture from which they emerged: a tough, scrappy, hyper-competitive world that was a far cry from the languid charm and amateur management of merchant banks.

Terry Smith, chief executive of Tullett Prebon, once described inter-dealer broking to me as "a full-contact sport", and the British are accustomed to playing such games without helmets or body armour.

There are still some barrow boys in inter-dealer broking, but it has evolved into more an attitude of mind than a matter of social class. Mr Smith was born to a lorry driver in London's East End, and still has the accent, while Michael Spencer, Icap's chief executive, grew up in Asia and Africa as the son of a colonial administrator before attending a Sussex boarding school and Oxford University.

It does not seem to make a lot of difference. Mr Smith certainly relishes a good fight: last year, the Financial Times paid Collins Stewart Tullett, from which Tullett Prebon demerged, £300,000 damages in a libel settlement.

But Mr Spencer, despite his smoother manner, has been no less assertive or demanding in building up his broking business, which he founded in 1986 with £50,000 in capital. Mr Smith's latest US sally is typical. His bid for eSpeed follows an attack on Howard Lutnick, chief executive of Cantor Fitzgerald, by the hedge fund Chapman Capital, which accused Mr Lutnick of abusing control of eSpeed, through a dual-share structure.

In the short-term, it will not work. Mr Lutnick is at least as tough a fighter as Mr Smith. He rebuilt Cantor Fitzgerald after 660 of its employees died on September 11th, 2001 and he is determined not to let eSpeed be taken away. But Mr Smith has spotted a flaw in Mr Lutnick's defences and history suggests he will not be in a hurry to abandon this fight.

Persistent awkwardness has worked for Mr Smith until now and he will probably stick with it. That is not what foreigners expect of the British, but it is harder now to dismiss them as flaky. That may have been true of the gentry that used to run London's merchant banks, but the inter-dealer brokers are cut from another cloth. Here come the barrow boys.

• Lucy Kellaway is on leave.