Abigail lived in a Nigerian suburb, making ends meet by selling pies to construction workers.

One of her customers, who owned a nearby building firm, offered to help her get a job in the UK to follow her dream of becoming a nurse. After six months of winning her friendship, he even paid for her plane ticket there.

“I was happy, thinking that he’s a nice man,” says Abigail, now 36 and too terrified to use her real name. “That’s how he brought me to this country – only it was prostitution that he introduced me to. He wanted me to make money for him.”

As soon as she arrived at Gatwick, her “friend” changed. He told her she would have sex with strangers for money, and that he wanted to make “thousands” from her.

He bundled her to a dingy London flat where women waited, terrified, in the kitchen for two bedrooms to become free so they could be forced to take turns sleeping with the men who had paid to have sex with them.

“I told him I don’t want to do that, I can’t do that. But he said I’m a slave to him from now on,” says Abigail. “He said I am nobody.”

Beaten when she resisted, Abigail was made to work as a prostitute “every day – that’s what he’s happy about, because every hour he makes money out of you”.

Since her captor had threatened her children back in Nigeria through relatives, Abigail believed she or they could be killed if she tried to escape. “You become so scared,” she says.

Abigail was trapped in this situation for years. Only last year was she freed when the brothel in central London where she was then working was targeted in an immigration raid.

She was referred to Hestia, a charity whose services include support for victims of human trafficking. They listened, they talked with her, and they helped. She threw herself into volunteering for a church to give her life a sense of purpose. Finally, she says, she is slowly beginning to put her life back together, day by day.

It seems impossible that cases such as Abigail’s can still exist today. Yet they do. We have already talked with many people who have found themselves just as trapped. That is why The Independent, in partnership with our sister paper the London Evening Standard, is today launching a special investigation into the scandal of modern slavery in today’s Britain.

Abigail is still afraid for her family and waiting on an asylum claim. But she knows that there are others whose situation is worse. The Independent Anti-Slavery Commissioner, Kevin Hyland, says there are up to 13,000 people in Britain trapped in modern slavery, many of them facing daily ordeals just like those Abigail had to endure.

Most of these cases go unnoticed. In 2016, the National Referral Mechanism assessed 3,805 potential victims of modern slavery in the UK, more than double the figure from 2013. Many are trapped in cultures of abuse, in alien environments where they do not speak the language. But the victims are not only from abroad. Of the potential victims assessed last year, the third largest group by nationality was British. Most go unnoticed by the authorities. But we know the numbers are likely to be getting worse.

“Victims of the crime are relentlessly abused and repeatedly raped,” says Mr Hyland. “Their dignity is denied and freedom taken. This isn’t a crime that is hidden and impossible to detect – it is happening before our eyes. It’s a huge problem, horrifying in its inhumanity, but it is one that we can all work to eradicate.”

This evil phenomenon is all around us. The busy professional who goes for a manicure, gets their car washed, buys UK-grown marijuana at the weekend, maybe goes for dinner at the house of a rich friend with live-in staff, could easily think slavery was a problem for another country or era. But those activities are all the most common areas where slavery can be found in the UK today.

Over the coming weeks and months The Independent will be exploring the scale and scope of modern slavery today, speaking to everyone from law enforcement, political and business leaders to victims and victim support groups, in order to show readers the extent of the problem. We will also be taking practical steps, with measures and proposals to help end slavery wherever it is found, from victim support to stamping it out in corporate supply chains. In February we will present ideas to the Santa Marta anti-slavery conference at the Vatican.

“The awareness isn’t there yet,” says Mr Hyland. “If you see something that looks bad – if six people are washing your car for £4, or if the person doing your nails isn’t allowed to talk to the clients – then say something. Once the public says this is unacceptable, then the agencies who work for the public have to take more action. Modern slavery manifests in different ways, and sometimes there’s discussion about whether ‘slavery’ is the right term to use. Absolutely it’s right. It’s crucial we understand it for what it is. It’s where somebody takes control of a person and turns them into a commodity.”