> Few skyscrapers were built in London before the late 20th century, owing to restrictions on building heights originally imposed by the London Building Act of 1894, which followed the construction of the 14-storey Queen Anne's Mansions.
Though restrictions have long since been eased, strict regulations remain to preserve protected views, especially those of St Paul's, the Tower of London and Palace of Westminster, as well as to comply with the requirements of the Civil Aviation Authority.