The International Day for the Abolition of Slavery is observed annually on 2 December to focus on the elimination of human trafficking, child labour and other forms of modern-day slavery.

Around 21 million women, men and children are still trapped in slavery worldwide, from the forced employment of children in conflict to sexual exploitation.

Aidan McQuade, director of charity Anti-Slavery International, explains to IBTimes UK what modern slavery is, how prevalent it is in the UK, and what needs to be done to tackle the problem.