Modern slavery: 'I was paid nothing for nine months'
16 December 2013 Last updated at 18:01 GMT
Life sentences will be brought in as part of a package of measures being proposed by Home Secretary Theresa May to tackle human trafficking and modern slavery.
The draft Modern Slavery Bill aims to increase the maximum jail sentence for offenders from 14 years to life.
Newsnight's Jim Reed spoke to Mark, who lost his job in 2009 and whose relationship had fallen apart. He was offered paid work and a place to stay by a man who saw him coming out of a soup kitchen.
But, after a series of moves, and some initial paid work, he found himself living on what he said was a travellers' site and forced to work as an unpaid labourer against his will for nine months.
Watch the Newsnight film in full on Monday at 22:30 GMT on BBC Two or later on the BBC iPlayer.