IN OUTWARD APPEARANCE Professor Jack Tagg looks more like a jazz musician of the 1950s than a retired academic. So uncanny is this resemblance to some gnarled survivor from the age of be-bop that those watching his denimjacketed and peak-capped figure lumbering towards them at a literary festival, the quarterly literary magazine whose business Professor Tagg has conducted since the days of Mrs Thatcher’s second term.