Media playback is unsupported on your device Media caption 'Jamusz', who was trafficked to the UK from Poland, tells his story

The number of people reported as potential victims of slavery and human trafficking in the UK has more than doubled in the past three years.

Statistics released by the National Crime Agency (NCA) show there were 3,805 people referred for help in 2016 - up from 1,745 people in 2013.

Recent Home Office estimates suggest there are between 10,000 and 13,000 victims of modern slavery in the UK.

Home Office minister Sarah Newton said the government was taking action.

Albanian, UK and Vietnamese nationals are the most commonly reported victims of modern slavery.

'Traded like commodity'

Tamara Barnett, from the Human Trafficking Foundation, said she believed the rise may be down to an increased understanding of what constitutes human trafficking and modern slavery.

"We are starting to recognise a lot more cases as being human trafficking cases," she said.

Image caption The Salvation Army says many people are trapped in poorly paid jobs after being trafficked

"It used to be very much seen as just the trafficking of women into the sex trade.

"There was quite a narrow view of what it involved but now there is definitely a broader view of what is human trafficking."

She said the increased awareness was in part due to the introduction of the 2015 Modern Slavery Act, which requires all public authorities to notify the Secretary of State or relevant authority if it has "reasonable grounds to believe that a person may be a victim of slavery or human trafficking".

However, she said additional training and funding was needed to improve awareness of the issue and called for better long-term support for victims.

'I was scared for my life'

Image caption The victim was speaking under a pseudonym to protect his identity

A man who was trafficked to work in the UK from Poland has spoken to the BBC about his experience working in the West Midlands.

Using the pseudonym Jamusz to protect his identity, he said he met a man in the job centre in Poland who told him he would earn more in the UK.

"To begin with it was really good, then they started taking half my money and I felt like I was imprisoned," he said.

"I started work at 7.30am and finished at 17:00. I should have earned between £380-£400 a week.

"The money was being transferred into my bank account, but when I went to withdraw it, a person came with me and I would only get half of it.

"I realised this was definitely wrong and I escaped."

Jamusz spoke to police who helped him move to a safe house in Leeds.

"Police kept coming to the place where we were working for checks," he said. "One day they raided the warehouse, and I told the police everything.

"I was scared for my life. Here, my life has definitely got better since I escaped."

Figures from the NCA also suggest more children are potentially being trafficked for sexual exploitation, with the number reported to agencies having doubled in the past 12 months from 105 cases in 2015 to 215 in 2016.

The Salvation Army, which works with people who have been trafficked, said cultural practices, beliefs, poverty and a lack of education are used to "trick" people into being trafficked and enslaved.

"They all have one thing in common - the victims themselves are vulnerable individuals who are lured into a false sense of security or obligation," spokeswoman Anne Read said.

"They're traded like a commodity. In almost every case somebody has been told that there is a job for them, and they follow that person to our country."

She said it was important people were alerted to the problem and reported any suspicions to the authorities.

"Rather than mind our own business we should make it our business," she said.

"Britain is both a source and destination country for men, women and children subjected to sex trafficking and forced labour, including domestic servitude."

Ms Newton, minister for vulnerability, safeguarding and countering extremism, said: "Modern slavery is a barbaric crime which destroys the lives of some of the most vulnerable in our society.

"This government has taken world-leading action to tackle it, giving law enforcement agencies the tools they need, toughening up sentences, increasing support for victims and encouraging more to come forward."

She said the government also funded a specialist victim care contract, delivered by the Salvation Army, for victims.