A “Global Slavery Index” has been released which shows the number of people trapped in modern slavery across the world, and ranks 162 countries accordingly.
India was found to have almost 14 million people living in conditions of slavery – nearly half of the entire number of 30 million worldwide.
In terms of proportion of its population, Mauritania ranked the worst – with as many as 4 per cent of its people regarded as slaves largely because they inherit the status from their ancestors.
The UK was ranked joint-last in this proportionate table, tied 160th with Ireland and Iceland, but the report carried a strong warning that this does not mean the countries are slavery free.
“On the contrary, it is estimated that there are between 4,200 and 4,600 people in modern slavery in the United Kingdom alone,” it said.
“An analysis of the UK response on this issue confirms much more can be done, as the Government response is fragmented and disjointed, and that there have been alarming systemic failures, including the loss of trafficked children from care.”
The index was produced by the Walk Free Foundation, an Australian-based organisation founded last year which campaigns for human rights and has been endorsed by influential figures including former US Secretary of State Hillary Clinton and Microsoft co-founder Bill Gates.
Ms Clinton said in a statement that although the index wasn't perfect, it provided a starting point.
“I urge leaders around the world to view this index as a call to action, and to stay focused on the work of responding to this crime,” she said.
WFF classed a number of different practices, customs and abuses under the broad term of slavery, which included debt bondage, forced marriage, human trafficking and the use of child soldiers.
The numbers produced are estimates, based on a detailed analysis of government reports, statistical releases and the work of non-profit organisations.
“A lot of governments won't like hearing what we have to say,” WFF chief executive Nick Grono told the French news agency Agence France-Presse.
“Those governments that want to engage with us, we will be very open to engaging and looking at ways in which we can better measure the issue of modern slavery.”
The report said the west-African nation of Mauritania had around 150,000 people living as slaves, out of a population of just 3.8 million.
In terms of proportionate rates, Haiti came second – with around one in 10 children used for child labour in an exploitative system.
Pakistan came third – in both the proportionate and total rankings – with 1.8 million people forced into bonded labour, out of a total 2.1 million people in slavery.
India, which ranked fourth proportionately because of its enormous population, had the highest number of people living in slavery by some margin due to the relative abundance of child labour and forced marriages.
Russia was the worst-faring European country in the list. With more than 500,000 people living in conditions of slavery, it ranked 49th in the proportionate table.
In absolute terms, China, Pakistan and Nigeria followed India, and along with the rest of the top 10 countries made up three quarters of the entire world’s population of people living in slavery.
Countries ranked by estimated number of slaves
India - 13,956,010
China - 2,949,243
Pakistan - 2,127,132
Nigeria - 701,032
Ethiopia - 651,110
Russia - 516,217
Thailand - 472,811
DR Congo - 462,327
Burma - 384,037
Bangladesh - 343,192