The late "Colonel" Richard Seifert, commercial architect to postwar London, designed the NatWest Tower alongside, but before that he had a golden period in the 1960s when he did quite radical things with ordinary building types like office blocks and hotels, using big prefabricated components. There are a couple of circular Seifert buildings from this period, in Covent Garden and Knightsbridge, that sprang unbidden to my mind as I walked up to the base of the Gherkin. You get the same feeling of big, heavy structure hanging above your head, unmediated by much in the way of intervening fine detailing. Foster's team has hacked an entrance through the lattice steel structure of the Gherkin much as someone might (to switch vegetables for a moment) carve a jagged smile into the face of a Halloween pumpkin. It is crudely done.

You wish that Foster could have given the base of his tower a touch of delicacy as he did at the top. After all, most people only see it at two magnifications - either close-up at street level, or from a great distance, on the skyline. American architects have long understood that where a skyscraper hits the ground, a different architecture can be deployed. Foster does this to an extent - beneath the raised, jagged-edged skirt of the structure the building turns into a smooth recessed cylinder, round which runs the sheltered ambulatory, which will contain little shops and cafes to serve the granite- paved plaza in which it sits. So perhaps I am carping about nothing. Anyway, I like the Gherkin enough not to care. If it wants to get a touch brutal at ground level and remind me of Seifert, well, I can take it.