Shawn Donnan and Sam Fleming in Washington:

The Pew researchers, however, found that even taking its broadest definition and counting those living on between $10 and $100 a day, just 1.7bn people could be considered middle class at the end of the first decade of this century.

“The global middle class is smaller than we think, it is less well off than we think, and it is more regionally concentrated than we think,” said Rakesh Kochhar, the lead author.

Globally, Pew said, 71 per cent of the world’s population still ranked as poor or low-income in 2011, the latest year for which all global data are available, compared with 79 per cent in 2001.