Kevin Hyland, the UK's independent anti-slavery commissioner is calling on people living in London to help police combat sexual slavery that was "blighting the capital."
"It's up to the public to come forward," Kevin Hyland said.
"People who live in a street where there is a brothel operating will see obvious signs of numerous women arriving, young women often, they may arrive escorted, they may be there late at night, there will be people regularly coming to the door."
According to Mr. Hyland, more than 3,000 potential victims of slavery have been identified by police across the country — and that number is rising.
"The figures from the Met are significantly up — they are running at almost 500 cases in the first seven months so they are going to be close to 1,000 cases this year," he said.
Since legislation was introduced in Britain to combat modern slavery, there has been a 40 percent increase in the number of victims referred for support. There has also been a rise in the number of convictions for human trafficking — up from 130 to 192.
Mr. Hyland admits the public will find it "shocking" and "a horror that this goes on," however he says London's Metropolitan Police Service take human trafficking as one of the most serious crimes in the capital.
Elsewhere in the UK, police recently voiced their concerns over so-called "pop-up" brothels in the Cornish seaside resort of Newquay.
Two have been discovered so far this summer but because of the very temporary nature of the brothels — often only open for a week — it's difficult for police and the public to spot the signs.
Inspector Dave Meredith said: "The booking is usually for one week, after which the premises is vacated and, due to the short period of time the premises is used as a brothel, it is often difficult for police to establish that sex workers are residing there before they move on."
Police in Newquay are concerned about the increase in the number of sex workers in the area, which means more women are being exploited.
"Women who work in these pop-up brothels are often subjects of human trafficking and work under duress."
"Modern slavery is of concern to us all and includes sex trafficking where women are forced into the commercial sex industry and held against their will be force, fraud and coercion," Inspector Meredith said.
The UK anti-slavery commissioner is hoping that members of the public will help uncover brothels or apartments used in London for prostitution purposes, many of which are set up on residential streets.
A report published in 2013, highlighted major concerns about the scale of human trafficking in England. The report, "Shadow City," suggested nearly 50 percent of modern slavery victims are found in London and the Home Counties.
Three years later and UK's anti-slavery commissioner is calling for Londoners to be more aware of what's going on around them to help combat sex slavery in Britain's capital.
According to the report, in London, you are never more than a few hundred yards away from a victim of human trafficking.