Old money is struggling to keep pace with the new wealth flooding into Britain from abroad, according to the Sunday Times Rich List.
Of the 117 billionaires on this year's list, only 62 are British-born.
The Queen has dropped out of the wealthiest top 300 for the first time, despite increasing her wealth by £10 million ($19.9 million) this year to £340 million.
Most of the billionaires in London are from abroad but use the capital as a base because of the accommodating tax regime, the legal system, language and its position in Europe.
The 117 billionaires have a total wealth of £325 billion.
Only two of the top 10 are British: the Duke of Westminster, worth £8.56 billion, is in ninth place, and Galen Weston and family, whose retail empire includes Selfridges, are in third place with an 11 billion fortune.
Mere millionaires struggle to join the mega-rich, with £100 million required to make it into the top 1000.
Topping the list is the London-based Ukrainian businessman Len Blavatnik, whose empire includes the Warner Music Group. His fortune is estimated at £13.17 billion.
The fall in the Queen's ranking is in part attributed to the fact that the list now excludes the value of things such as the royal art collection.
New entries include actor George Clooney and his wife, Amal, who have a combined wealth of £121 million.