Campaigners fear the easing of coronavirus lockdowns could spark a rise in exploitation, as businesses scramble to recruit low-paid workers.
Look around London and it’s difficult to spot. But slavery is a thriving, criminal industry in modern Britain: victims falsely promised the world – and then exploited, abused, sometimes left fearing for their lives.
Last year, a record 10,600 people were identified as potential victims of modern slavery in the UK, a rise of more than 50 percent on 2018.
Labour exploitation was the most common form of abuse, with many of the victims coming from the UK, Albania and Vietnam.
Victims can end up in nail bars, car washes, farms and factories.
The charity Hestia, which supports survivors, fears there could be more exploitation as the coronavirus lockdown is eased.
"As those businesses are allowed to open up again, we think the number of people being exploited in those industries will begin to increase again," said Ella Read, of Hestia’s modern slavery response team.
"And the risk is potentially higher, given that businesses and employers might not have as much money to provide for their wages and all of those kinds of things," she added.
Hestia, which has just opened a new safe house for survivors, doesn't think travel restrictions will stop the traffickers.
"Unfortunately, they will find more creative ways to either move individuals between other countries or bring individuals into the UK itself but also the risk to British nationals may well increase as well," Read said.
The UK has stepped up its efforts to tackle slavery, but critics say new laws introduced in 2015 are not being used enough.
Nancy, who did not want to give her surname, is a slavery survivor who supports others. She thinks victims must be given legal status to stay in Britain.
"This will help survivors to rebuild their lives because having legal status is where freedom begins for survivors. Without having legal status, survivors are put in even more vulnerable positions whereby we face re-trafficking and re-exploitation," she said.
Unmesh Desai, a Labour party politician and chair of the police & crime committee at the London Assembly, scrutinises crime-fighting in the capital.
"Very very few prosecutions have been brought under the Modern Slavery Act and it's about stepping up enforcement action. And I would say that a fair bit has been done, but a lot more needs to be done," he said.
You can watch Damon’s full report in the video player above.