For many years the 183m-tall Nat West Tower (as it was originally known) was probably the tallest and most iconic tower in the City of London. It shares honours with Centre Point as one of Seifert's most striking additions to the city's skyline. It was originally designed as the HQ of the National Westminster Bank. The floor plan bears a striking resemblance to the bank's logo, and there is some debate as to which came first. All the floor plates cantilever from the massive central core. This means that the useable floor space is an irregularly shaped perimeter ribbon. In most structures of this age, this poor space efficiency would normally lead to demolition, but this was calculated to be too dificult and too costly. So in 1993, following terrorist bomb damage, the building was refurbished by GMW, who also added a glazed three-storey entrance lobby at the base. At the same time the building was rebranded as Tower 42.