The Modern Slavery Act 2015 is an Act of the Parliament of the United Kingdom.It is designed to tackle slavery in the UK and consolidates previous offences relating to trafficking and slavery. The act extends to England and Wales.The bill was introduced to the House of Commons in draft form in October 2013 by James Brokenshire, Parliamentary Under Secretary for Crime and Security.The bill's sponsors in the Home Office were Theresa May and Lord Bates. It received Royal Assent and became law on 26 March 2015.he act extends to England and Wales. The bill was introduced to the House of Commons in draft form in October 2013 by James Brokenshire, Parliamentary Under Secretary for Crime and Security. The bill's sponsors in the Home Office were Theresa May and Lord Bates. It received Royal Assent and became law on 26 March 2015.