This law is currently only in place in Northern Ireland. It doesn't apply to the South or to anywhere else in the UK and was recently rejected by both Westminster and the Scottish Assembly. Despite what you may have heard, the law isn't about coercive trafficking, rather a disapproval of sex work in general.
The law doesn't make it illegal to visit an escort, but it does criminalise the purchase of sex. How this can actually be proved remains unclear.
2014 in Northern Ireland:
Number of reported attacks on sex workers 70
Number of sex trafficking cases ZERO