Off to Lord Foster's City Hall, where the long-winded public examination of Mayor Livingstone's London Plan is taking place. An entire day last week was devoted to questions of heritage and tall buildings, with contributors seated around the horseshoe council chamber, gazing through the glazing at the panorama on the other side of the Thames, including Tower 42, the Tower of London and Lord Foster's gherkin. Arguments raged about the sequence of identifying locations for tall buildings - or did locations mean sites? According to English Heritage and the Royal Parks Agency, a major exercise should be undertaken to identify potential locations/sites prior to identifying any particular bit of London. The mayor's plan, on the other hand, suggests that studies should be carried out into whether tall buildings 'could' be appropriate over major interchanges, in Croydon and at Elephant and Castle. EH obviously fears that 'could'means 'will', which is not unreasonable. On the other hand, if you can't build tall buildings over interchanges, where can you build them? On sites devoid of public transport?