article_snippet: When Britain's richest woman Kirsty Bertarelli came to extending the former Miss UK’s London home, however, excavating a vast two-storey subterranean extension seemed the perfect solution.
article_snippet: Some homes on the Bertarellis’ mews, one of the most affluent areas of the capital, already have basements, but several neighbours had instructed lawyers to fight the latest proposal.
article_snippet: While the latest proposal will be the third property to have a basement, Bertarellis would be the first to excavate to two storeys.
article_snippet: In the past few years there has already been one double basement conversion and a single basement.
highlights_snippet: Kirsty Bertarelli, 43, is building the basement at her three-storey mansion .
  
highlights_snippet: Ernesto will be first home on road to excavate two floors .
  