Today marks the first international day of prayer and awareness against human trafficking.

The event is being organised by the Catholic Church, who are calling for people "to join in prayer" for people who are trapped in slavery and trafficking.

It is estimated that 2.5 million people are victims of trafficking and slavery every year, with many of them suffering abuse and violence.

The Vatican says this particular date has been chosen as it is the Feast Day of St Josephine Bakhita, who was sold into slavery as a young child and whose struggle for liberation provides hope.

Martina Liebsch, policy and advocacy director of Caritas Internationalis, said we must all take responsibility "by being aware, by recognising the signs, by looking at our neighbours, brothers, sisters, people we meet on the street and by asking ourselves under which condition does this person live?".

"It is also a call to employers to give people work conditions that are not exploitative...to improve working conditions and fight against slavery," she added.

She also points out that trafficking is often closely linked with migration - especially migration from poorer countries - where they are particularly vulnerable as they hope for a better life, and then become trapped in the mechanisms of traffickers.

Official figures show it generates some $US32bn (€28.2bn) a year - making it the third most profitable 'business' after drugs and arms trafficking.

While Pope Francis has called for help for "the many men, women, and children who are enslaved, exploited, abused as instruments of labour or of pleasure, who are often tortured and mutilated."

He called on government leaders to act decisively "to remove the causes of this shameful wound".