The number of victims of trafficking and modern slavery helped by the Salvation Army in England and Wales has increased nearly fivefold since 2012, the charity said on Monday.
The increase reflects a rise in both the number of people being exploited and in the number of those seeking help as awareness of the issue has grown, the Salvation Army said.
The charity helped more than 1,800 victims of trafficking and modern slavery between April 2015 and March 2016, up from 378 between July 2011 and July 2012, it said in a report.
"As knowledge and support [for trafficking and modern slavery] grows, there's more likelihood that people will take up the offer of support," said Anne Read, director of anti-trafficking and modern slavery at the Salvation Army.
"Greater awareness without a shadow of a doubt is resulting in more people being identified," she told the Thomson Reuters Foundation in a phone interview.
There are an estimated 13,000 victims of forced labor, sexual exploitation and domestic servitude in Britain.
Globally, forced labor generates an estimated $150 billion in illegal profits every year.
The Modern Slavery Act - which came into force in Britain in 2015 - increased maximum jail terms for traffickers from 14 years to life and brought in measures to protect people feared at risk of being enslaved.
Of those seeking help from the Salvation Army, 269 were from Albania, 148 from Poland and 136 from Nigeria, said the charity, which provides support services including accommodation, legal advice and counseling.
"For many years, the biggest source country [for people trafficked to Britain and Europe] was Nigeria [but] over the last two years there's been a shift to Albania," Read said.
Some 44 percent of victims had been subjected to sexual exploitation, 42 percent had been exploited for labor and 13 percent had been victims of domestic servitude, the report said.
The region with the highest number of referrals to the Salvation Army was London (29 percent), followed by the South East and West Midlands, both with 16 percent.
Read said that even though more victims of modern slavery and trafficking were seeking help, the government needed to step up efforts to combat the problem, including raising awareness and providing economic options in the victims' home countries.
She said better data meant it was now possible to trace victims' origins to specific regions, even towns and villages.
"We have that data now and targeting those places with awareness-raising resources is certainly one of the things we can do," Read said.
"The other thing is giving realistic economic options in those places because where people are still feeling so desperately hopeless, they might still risk the possibility of a better future if that opportunity is afforded them."
Around the world, almost 46 million people are trapped in slavery, with the greatest number in India and the highest prevalence in North Korea, according to the Australia-based human rights group Walk Free Foundation.