ITV News report by Political Correspondent Libby Weiner
Britain will lead the way in ridding the world of the "barbaric evil" of modern slavery, Theresa May has vowed.
The prime minister has pledged an extra £33 million and set up a new government taskforce as part of the crackdown.
She said the money would be used to deal with the routes of the people trafficking trade in countries like Nigeria.
Mrs May wrote in the Sunday Telegraph about her determination to stop the illegal trade.
"This is the great human rights issue of our time and as Prime Minister I am determined that we will make it a national and international mission to rid our world of this barbaric evil."
Ministers have estimated that there are between 10,000 and 13,000 potential victims of slavery in the UK.
A review to mark the first anniversary of the Modern Slavery Act found that 289 modern slavery offences led to prosecution in 2015.
There was also a 40% rise in the number of victims who were referred for support, showing that the Act had been a success.
Labour said Mrs May "should be ashamed" of her record on protecting child victims of slavery.
"Modern slavery is on the increase but under Theresa May's watch, the police and Border Force have been cut and her government cut local authorities by over 40%," Sarah Champion, the shadow minister for preventing abuse, said.
"If Theresa May is serious about tackling slavery, she needs to give professionals the resources to stamp it out."