WHILE THE CRISIS in the Falklands seems to be moving toward a climax, Britain's relations with its friends and allies in Europe get steadily worse. Earlier this week, after much debate, the European Common Market grudgingly extended, for one week, its economic sanctions against Argentina. Both in the reluctance and the brevity of the extension, it was a remarkably unhelpful gesture. If it was intended to dissuade the British from further action, it will doubtless prove to have been a failure as well. It can only have been read in London as one more reason to get the affair settled fast.

After the split vote on sanctions, the Common Market then proceeded to take up the annual row over agricultural subsidies. It has been running more or less continually since Britain joined Europe nine years ago, and if it involved money alone, it might perhaps be soluble. But it acts as a magnet, drawing to it all the political suspicions and resentments that surround British membership.

The British tradition was low food prices and no farm price supports. The Continental tradition was the opposite. Britain understood, when it came into the Common Market, that its food would cost more. But no one foresaw, or could have foreseen, the huge contributions of cash that the arcane formulas of the Common Market would extract from Britain. The effect is, absurdly, that British consumers with their low incomes are heavily subsidizing the agriculture of Northern Europe with its very high incomes.

To force a better settlement this spring, Britain had been blocking the farm price increases that the rest of the Common Market wanted. There was an unwritten rule that no country was ever overridden on a matter of national interest--but on Tuesday, the others overrode Britain on the farm prices. The British were incensed. The French contributed their annual statement to the effect that they are fed up with the British--suggesting once again that the advent of a Socialist government in Paris has made fewer changes than you might think. The upshot is a great surge of ill feeling, far more than the farm quarrel normally generates. This time the votes seem clearly to imply a lack of support for the Falklands venture and perhaps even an inclination to take advantage of Britain's distraction.

As wars go, the battle for the Falklands is a small one. But it has already had startling consequences. For one thing, it may have transformed naval warfare. For another, it now seems to threaten real damage to the political base on which the Common Market stands.