The highest-earning one percent of UK society are increasingly London-based, with women slowing edging into the group, a new study by the Institute for Fiscal Studies (IFS) shows.

Being part of the one percent required a pre-tax income of at least £120,000, the IFS found. The top one percent of taxpayers in fact need to earn at least £160,000. However, 43 percent of UK adults do not earn enough to be subject to income tax, thus the lower threshold for the entire adult population. The study largely focuses on the top one percent of taxpayers - due to its reliance on tax data.

While this £160...