In a move that has been welcomed by campaigners, the Prime Minister has announced that Britain will sign up to a European convention to "stamp out" human trafficking.
He made the announcement at a Downing Street reception last night to commemorate the 200th anniversary of the abolition of the transatlantic slave trade.
It means trafficking victims will not be immediately deported, but given time to recover and consider testifying.
Mr Blair warned the "evil" of slavery was still around.
"There are still people that suffer tremendous injustice," he said.
"One of the things that we need to do is remind people this is an evil that is not yet stamped out in our world."
In March 2006, the Catholic Bishops‚Äô Conference called on the Government to sign and ratify the European Convention Against Trafficking.
Chief Executive of Evangelical lobby group CARE, Nola Leach, welcomed the move. ‚ÄúThe Convention ensures that a victim would be given a minimum 30 day ‚Äòreflection period‚Äô in which they would receive much needed medical and psychological care and an assessment of the danger they would face if returned home made. Although severely traumatised, many victims are removed within 48 hours, some being re-trafficked within days of their return.‚Äù
‚ÄúThe demand created by prostitution and lack of clear legislation has created a ready made market for traffickers to easily exploit. We hope that today marks a positive step to end the ease with which this trade operates.‚Äù
The move is the first in a series of commemorations to mark the bi-centenary of the 1807 Abolition of the Slave Trade Act.
A march is to take place in two months time, involving the Archbishops of Canterbury and York, to express repentance for the Church of England‚Äôs complicity in the slave trade.
Events will focus in particular on 25 March and Unesco's slavery remembrance day on 23 August, but there will be a series of events over the months including a service at Westminster Abbey, the launch of a commemorative ¬£2 coin and stamps bearing anti-slavery campaigners.
An international slavery museum will open in Liverpool, while the Wilberforce House Museum in Hull will re-open.
"What we are trying to do is plan a whole series of activities in order to make it clear that this is something which we want to catch people's imaginations," Mr Blair said.
He said this was "not just to remember things that happened 200 years ago but to remember ... the problems we still face today and how we've got to use some of that inspiration from that campaign 200 years ago, to motivate us in dealing with these challenges now."
The European Convention Against Human Trafficking covers a range of measures, including 30-day residence permits to victims to allow them to recover from their ordeal and reflect on whether they will help police prosecute offenders.
There are some fears this may be open to abuse by people making false claims of being trafficking victims to remain in the country.
But the Conservatives have also said Britain should sign up to the convention, saying human trafficking was "spiralling out of control".
Although tens of thousands of women are thought to be involved, between 2004 and 2006 there were only 30 convictions for trafficking offences, they say.
Downing Street said allowing victims time to recover would encourage them to pursue those responsible.
Dr Evan Harris, Liberal Democrat member of the Joint Committee on Human Rights, said: "While I welcome the UK signing this important convention, the government has never explained why it couldn't have done this 18 months ago and started taking the urgent steps required to comply with it and ratify it."
He said the government had not produced a "shred of evidence" that meeting the needs of trafficking victims would have any effect on immigration control.
"While the government has dithered, vulnerable women and children have been left at risk and traffickers have escaped prosecution."