There was a time when the home affairs debate at the Conservative Party conference was dominated by crime. Nowadays, immigration and human rights take centre stage. And increasingly the two go together. Theresa May's announcement yesterday of a Bill to curb modern-day slavery is a corollary of the ease with which people can move around the world. Human trafficking is an aspect of organised crime and illegal immigration; and it is particularly galling, then, to find that human rights laws and the courts block the deportation of those convicted of such offences.