In 1992 I wrote a column that was published under the headline ‘It’s Time to Split the Tate’. To my absolute astonishment, shortly afterwards it was announced that this would actually happen (no doubt a coincidence rather than a response to my words). Hitherto, though it is hard now to recall those times, there had been just a single Tate gallery in London — the one on Millbank, containing a cheerful jumble of British painting from the Tudor era onwards mixed with what was then described as modern ‘foreign’ art.