Three of the world's smallest states have been named as the richest countries in a new study.

Qatar, Luxembourg and Singapore came top in the research which ranked countries by their wealth according to their gross domestic product.

Both the U.S. and Australia made the list's top ten but Britain was named the 23rd richest country behind states such as Ireland, Taiwan and Kuwait.

The data provided by the International Monetary Fund and compiled by the Global Finance Magazine, also took into account purchasing power parity, which analyses living costs and inflation rates.

Using this measure, gulf state Qatar came top of the list with a GDP in 2014 - 2015 of $105,091 (£67,497) per person.