For me, the event of the year was the simultaneous arrival in London of the thrilling Aztecs exhibition, drawn from the best collections of such art in Mexico City, and of the Chapman brothers’ brilliant modern parody of shows exactly like the Aztecs exhibition. For the month that they were on in tandem, these two perfectly matched displays seemed to mount a delightful fencing match between them for possession of the same patch of ethnic credibility. The Aztecs was compelling because the things in it had so much forceful strangeness about them: the art of the heart-rippers was bloody amazing. But the skill and determination with which the Chapmans created their hilarious collection of utterly convincing tribal objects and perpetuated their well-timed fraud, was at least as impressive. A further by-product of this serendipitous twin appearance was the shadow it cast over this year’s Turner Prize. The worst yet. Why is nobody of the Chapmans’ stature in it any more? I would have liked to welcome the new director of the National Gallery unreservedly, but find myself unable to do so. Neil MacGregor has only been out of the job for a few months, yet already I find myself plunging into recurring depressions at the prospect of his successor’s reign. By putting on a selection of paintings by Rolf Harris, Charles Saumarez Smith has signalled his intention to dumb down the gallery with alarming clarity.