30 St Mary Axe to flight paths for both London City and London Heathrow airports; the revised plan for a lower tower was accepted. The tower's topmost panoramic dome, known as the "lens", recalls the iconic glass dome that covered part of the ground floor of the Baltic Exchange and much of which is now displayed at the National Maritime Museum. "The Gherkin" nickname was applied to the current building at least as long ago as 1999, referring to that plan's highly unorthodox layout and appearance. On 23 August 2000, Deputy Prime Minister John Prescott granted planning permission to construct a building much larger
30 St Mary Axe and neighbouring structures. The United Kingdom government's statutory adviser on the historic environment, English Heritage, and the City of London's governing body, the City of London Corporation, were keen that any redevelopment must restore the Baltic Exchange's old façade onto St Mary Axe. The Exchange Hall was a celebrated fixture of the shipping market. English Heritage then discovered that the damage was far more severe than initially thought, and they stopped insisting on full restoration, albeit over the objections of architectural conservationists. The Baltic Exchange and the Chamber of Shipping sold the land to Trafalgar House in 1995. Most of