A "modern slavery" bill that tightens the laws on human trafficking will be introduced in a bid to help to eradicate an "evil in our midst", Theresa May has announced.

The home secretary said that prosecution rates for human trafficking were still shockingly low across Europe and that an overhaul of the law was needed because there was still some uncertainty over which agencies should be tackling the problem.

The bill, which will be introduced before the current session of parliament ends next spring, will consolidate existing anti-trafficking legislation in one place as well as toughening it.

New trafficking prevention orders, modelled on sexual offence prevention orders, will be introduced, allowing the courts to impose restrictions on the ability of offenders to own a company, visit certain areas or work with women or young children after their release. May believes these are necessary because people convicted of trafficking often return to the trade after their release from jail.

A "modern slavery commissioner" will be appointed to ensure that the government and law enforcement agencies are tackling the problem vigorously.

It is also possible that the bill could establish new classes of crime aggravated by a link to human trafficking. This would allow higher penalties to be imposed for offences involving, for example, drugs or prostitution, if they were part of a trafficking operation.

Writing in the Sunday Times, May said that she wanted the new National Crime Agency (NCA), and all police forces in England and Wales, to make the issue a top priority.

"It is scarcely believable that there is slavery in Britain, yet the harsh reality is that in 2013 there are people in this country forced to exist in appalling conditions and often against their will," she wrote.

"The criminals who exploit, bully and threaten them often inflict violence mercilessly. They are careful to ensure their victims have no rights. Those victims are, to all intents and purposes, slaves."

May said that, although the NCA was being told to focus on the issue, "as things stand, the law and the institutions we have for implementing these changes and sharpening our response make the NCA`s task more difficult than it ought to be".

She said: "For too long modern slavery has been seen as someone else`s problem. Some believe it is an illegal immigration problem, others that it should be tackled through victim support, but most importantly many don`t see it for what it is.

"So let me tell you what I believe it to be. It is a horrendous crime, it has got to stop and it is everyone`s problem."
May also explained why she was introducing trafficking prevention orders.
"At present, someone who is convicted of involvement in trafficking will receive a sentence of perhaps two years.

They will usually be out of jail within a year, and they will often go straight back to the business of smuggling people into this country so they can be made into slaves.

"Trafficking prevention orders will ensure that someone released from a sentence for a human trafficking offence cannot simply go back to being a gangmaster. They will also place restrictions on the convicted individual`s ability to own a company, or to visit specific premises and areas or to work with children or young women."

She also said that she would like companies to make an explicit commitment not to use suppliers reliant on slave labour.

Law@guardian