There are, shock­ing­ly, more peo­ple in slav­ery to­day than at any time in hu­man his­to­ry but cam­paign­ers think the world is close to a tip­ping point and that slav­ery may be erad­i­cat­ed in the next 30 years. The es­ti­mat­ed num­ber of peo­ple in slav­ery-27 mil­lion-is more than dou­ble the to­tal num­ber be­lieved to have been tak­en from Africa dur­ing the transat­lantic slave trade.

Ship records make it pos­si­ble to es­ti­mate the num­ber of slaves trans­port­ed from Africa to the Amer­i­c­as and the Caribbean, from the 16th Cen­tu­ry un­til the trade was banned in 1807 and the fig­ure is about 12.5 mil­lion peo­ple.

The fig­ure of 27 mil­lion slaves to­day comes from re­searcher Kevin Bales, of Free the Slaves, who blames the huge fig­ure on rapid pop­u­la­tion growth, pover­ty and gov­ern­ment cor­rup­tion.

Many peo­ple still think of slav­ery as a thing of the past, but it ex­ists in many forms, on every con­ti­nent-rang­ing from sex and labour traf­fick­ing, to debt bondage where peo­ple are forced to work off small loans.

"I of­ten think about a quar­ry slave from North In­dia," says in­ves­tiga­tive jour­nal­ist Ben Skin­ner, who has trav­elled all over the world doc­u­ment­ing cas­es of slav­ery.

"I could go in at night and in­ter­view him, so I asked him why he didn't run away. It was be­cause he feared the ex­tra­or­di­nary vi­o­lence of the quar­ry con­trac­tor who held him to a mi­nus­cule debt.

"In his world, the con­trac­tor was god. He was not on­ly the tak­er of life but al­so the giv­er of sus­te­nance. When we look at why slav­ery has per­sist­ed we have to look at break­ing those cy­cles of de­pen­dence."

Was slav­ery al­ready en­dem­ic in Africa?

Skin­ner says that many of the slaves he met in In­dia had nev­er known a free life. They came from ex­treme­ly iso­lat­ed com­mu­ni­ties, and were not aware of their ba­sic uni­ver­sal rights.

But while de­vel­op­ing coun­tries have the high­est num­ber of slave labour­ers, de­vel­oped coun­tries with strong hu­man rights laws "fail to re­source the law en­force­ment to deal with the prob­lem in com­par­i­son to vir­tu­al­ly any oth­er law", says Bales.

US Pres­i­dent Barack Oba­ma re­cent­ly paint­ed a por­trait of con­tem­po­rary slav­ery. "It's the mi­grant work­er un­able to pay off the debt to his traf­fick­er," he said. "The man, lured here with the promise of a job, his doc­u­ments then tak­en, and forced to work end­less hours in a kitchen. The teenage girl, beat­en, forced to walk the streets."

The US gov­ern­ment spends bil­lions on tack­ling homi­cide, Bales ar­gues, but on­ly a frac­tion is spent on slav­ery "even though we know there are many more slaves than homi­cides in the US."

In Eu­rope too, vic­tims of slav­ery can­not al­ways re­ly on the law to pro­tect them. An­ti-traf­fick­ing char­i­ty Stop the Traf­fik cites a case where a girl was re­turned to Hun­gary af­ter be­ing traf­ficked abroad. Up­on her re­turn to sup­posed safe­ty, she was raped and re­turned to her traf­fick­ers.

As well as be­ing trans­port­ed out of Africa dur­ing the transat­lantic slave trade, slaves were al­so cap­tured and sold with­in Africa. Slav­ery is al­ready il­le­gal in every coun­try in the world.

"We have not quite reached the tip­ping point, but it's much more dif­fi­cult for coun­tries and com­pa­nies to get away with forced labour nowa­days," An­dreas says.

"There is rea­son to be op­ti­mistic. We have seen a sweep­ing change in re­cent years in terms of leg­is­la­tion and bet­ter reg­u­la­tion.

"There's a clear sign that more com­pa­nies are be­com­ing aware, and more gov­ern­ments are will­ing to take ac­tion. If we have the crit­i­cal mass of lead­ers ready to take ac­tion, then it can be erad­i­cat­ed."

Bales says there was a time when law en­force­ment agen­cies knew how to deal with a truck full of drugs, but lacked clear pro­ce­dures for deal­ing with a truck full of peo­ple. This is chang­ing, he says.

The UN's an­ti-traf­fick­ing pro­to­col talks about the "three Ps" - pros­e­cu­tion, pro­tec­tion and pre­ven­tion.

In Brazil, a na­tion­wide an­ti-slav­ery plan set out in 2003 in­tro­duced changes in reg­u­la­tion and labour in­spec­tion laws that have re­sult­ed in the free­ing of thou­sands of slave work­ers. Em­ploy­ers are put on an of­fi­cial "dirty list" if they are found to use slave labour. This cur­rent­ly in­cludes near­ly 300 com­pa­nies and in­di­vid­u­als. The ILO al­so works to help oth­er coun­tries al­so spot the "in­vis­i­ble signs" of forced labour.

In 2008 the state of Niger was found guilty by a West African court of fail­ing to pro­tect a for­mer do­mes­tic slave, and the gov­ern­ment or­dered to pay com­pen­sa­tion.

Dr Aidan Mc­Quade, di­rec­tor of An­ti-Slav­ery In­ter­na­tion­al, says that fol­low­ing the ver­dict, the news spread and large num­bers who were in forced labour sim­ply walked away from their sit­u­a­tion, some­thing they would have been too afraid to do be­fore.

These are some of the fac­tors that make slav­ery "a solv­able prob­lem with­in our gen­er­a­tion", Bales ar­gues, 25 to 30 years. (BBC)