"We few, we happy few, we band of brothers.” Well, not quite as few as Shakespeare claimed; and not that happy either; and, when it came to the treatment of French prisoners, distinctly unbrotherly.

The forthcoming film Agincourt is the latest addition to a long tradition of myth-making, reinvention and historical controversy that has been going on for six centuries.

From our side of the Channel, Agincourt is seen as an heroic battle won against all the odds; from the French side, the epic encounter tends to be either ignored or regarded as a typical act of British brutality. The British see Agincourt as a victory for the longbow; the French tend to blame the weather.

In the traditional British version, Henry V’s army of 6,000 men, despite a crippling forced march, defeated a heavily armed French army six or seven times its size. In 2005, however, Professor Anne Curry argued that, based on administrative records, the odds were probably rather less heroic: it was only perhaps 9,000 English against 12,000 French. Those figures have, inevitably, been challenged.

Last year, Christophe Gilliot, director of the museum at Azincourt (as the French insist on spelling the place), pointed out claimed that the English had slaughtered large numbers of unarmed prisoners. The French historian was quoted as comparing the English with war criminals.

Mr Gilliot later denied saying any such thing, but his protestations were drowned out by the chorus of outrage from British historians. Henry certainly did order the execution of prisoners, but such behaviour was par for the course in the horror of medieval warfare: neither English nor French contemporary sources criticised Henry for ordering the executions.

Both sides have always seen the battle through the distorting lens of patriotism. Laurence Olivier’s portrayal of Henry V in 1944 boosted to wartime morale. The French version of Wikipedia, however, portrays the defeat as a victory in disguise ... “a major cause of the rise of Joan of Arc and the investment in artillery that became a French speciality”

But of all the arguments adhering to the battle, none is more hotly denied, or more passionately believed than the notion that the V-sign was invented at Agincourt. It is said that because the French customarily chopped the index and middle fingers off captured archers, to prevent them from drawing their bows again, the English bowmen at Agincourt defiantly raised two fingers at the approaching French cavalry — a gesture maintained at some Anglo-French sporting fixtures ever since.

There is no evidence that the French cut off archers’ fingers, in this way, and the offensive sign gesture probably predates Agincourt by at least a century. But like all great myths, this one is impregnable.

The precise shape of the new film is unknown, but this much is certain: the English will win, bloodily; the French will lose, plaintively; and the great battle over what happened at the Battle of Agincourt will continue, gloriously.

Once more unto the breach . . .

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