Calling someone a "roast beef" is a strange insult, although in its way not much stranger than calling someone a "frog".

But the graffiti on the war memorial in Etaples, northern France, was clear: "Rosbeefs go home."

The rest of what was written on the monument in the cemetery in Etaples - "Saddam will win and spill your blood", "Dig up your rubbish, it is fouling our soil" - left no doubt about the attitudes of the graffitists.

But why should they have used the word "rosbeefs"? (The usual spelling for this particular French nick-name for the English is "rosbif" - the graffiti spelling is presumably an attempted translation.)

Rosbif has two distinct meanings, and only one of them is usually intended as an insult.

In the most popular cookery books of France... roast mutton and lamb are designated Rosbif de Mouton, and Rosbif d'agneau Kettner's Book of Table, by ES Dallas, 1877

"Rosbifs became a mark of the Englishman as far as the French were concerned in the 18th Century, simply because it was a very popular way of cooking," he says.

"That style began to apply to other meats cooked in the same way, so you would also have 'rosbif de mouton' and that sort of thing."

Thus an English term becomes part of the French vocabulary, like "le weekend", part of a spread of the English language which infuriates many French. Rosbif as a name for roast beef, however, carried on spreading and is now also used in Spain and Italy.

Pretty inoffensive

By 1850, the phrase had been extended to mean Englishmen themselves. William Makepeace Thackeray wrote in The Virginians: "Only my white cockade and coat had saved me from the fate which the other canaille [rabble] of Rosbifs had deservedly met with."

The heated argument between the UK and France over British beef, after France illegally maintained a ban on imports which the rest of the EU had lifted three years earlier, may have breathed new life into the insult.

"Rosbif" is a parallel insult to "frog", in that many English see it as being only mildly offensive.

It would surprise many casual users of the "frog" insult to know, however, that it dates back to the 1300s, and originally applied to the Jesuits and the Dutch, long before it referred to the French.

Marsh dwellers

"It only changed to the French when they became the national enemy of the English," says Jonathon Green, author of the Cassell Dictionary of Slang.

"It originally applied to the Dutch because they were seen as inhabiting marshland, but there are citations from 1805 onwards in which it applies to the French." This would probably have had less to do with living in marshland than with eating frogs.

A Paris butcher defies the French ban in 2000

But the world is full of national and racial insults based on what people eat. Green dubs it "gastro-nationalism", and says it has "the benefit of several antagonistic worlds: not simply racial difference, but those ever-absorbing bones of contention, manners and taste".

The Racial Slur database lists hundreds of such terms, including "locust eaters" for Afghans, "salmon crunchers" for Alaskans, and "goulash-heads" for Hungarians.