The tail-end of the 20th century saw an unprecedented investment in attention-grabbing, hi-tech arts buildings across the UK. But five years on, how have these millennium projects fared?
Paul Allen talks to architects, critics and directors as he visits the Lowry in Salford Quays, the New Art Gallery, Walsall, and the second-biggest free tourist attraction in the country, Tate Modern , where he reflects on the last five years with gallery director Nicholas Serota. Producer Jerome Weatherald