In recent years, the museum has undertaken a highly ambitious expansion programme, with a sequence of new spaces including the Ecology Gallery by architect Ian Ritchie - still looking very good after ten years - and the ingenious Dinosaur Gallery by Ron Herron, a freestanding gantry structure which contrives not to touch the Waterhouse interior at all. David Chipperfield, meantime, reorganised the central hall with aplomb. This updating process culminated two years back in the fundamental and successful redesign of the previously overlooked Geological Museum as the Earth Galleries by architects Pawson Williams and others. Thus revitalised, this section was linked through to the rest of the museum, duly rebranded as the Life Galleries. But evolution never stops. Now the museum is onto its next project, and it is even bigger. The aim is completely to rebuild the neglected western end of this great museum, where you and I are very seldom allowed to venture. It is the domain of the scientists. All in all, it will cost around £100m.

The first phase, known as the Darwin Centre and costing around £27m, is now built - though you'd be excused for not realising this, since it is largely hidden behind a pig-ugly 1930s concrete laboratory block. Early next month the contents of that block - in particular, an extraordinary historic collection of more than 20 million specimens in large spirit jars, some collected personally not only by Charles Darwin but even by Captain Cook on his 1768 voyage to Australia - start to be transferred to their new home. Thereafter the old concrete eyesore will be demolished, so revealing the Darwin Centre as a rather good new building in glass, terracotta and steel.