dj, I was reading about that earlier today (yesterday) while looking up some information about wealth distribution (got sidetracked from finding out about immigrants' wealth, but I'll post what I found out later). The IFS's publications are heavy going, but the gist of the paper I was reading is that they couldn't include the top 1% in their calculations, because it was impossible for HMRC to find out how much they're worth. It's very possible that the top 1% are worth 10s or 100s times more than the top of the next 99%. Frighteningly, these are people who are pulling politicians' strings and, even more frighteningly, are passing this wealth on to future generations of their families, so the situation will get worse. It is impossible for people to earn that kind of money by working. We are returning to the MIddle Ages.
There's also a very interesting course on (in)equality on FutureLearn.