Calling William Wilberforce...

For once, I'll let the facts speak for themselves.

From the BBC :

The government of Niger has cancelled at the last minute a special ceremony during which at least 7,000 slaves were to be granted their freedom.

A spokesman for the government's human rights commission, which had helped to organise the event, said this was because slavery did not exist.
[...]
At least 43,000 people across Niger are thought to be in slavery.

Representatives of the slaves, the government and human rights campaigners had been due to attend the event at In Ates, near the border with Mali.

A local chief had agreed to the release after the introduction of a new law, which punishes those found guilty of slavery with up to 30 years in jail.

Anti-Slavery International had described the ceremony as a historic step forward.

The British-based campaign group said the people who had been due to be freed made up 95% of the local population.

"The government needs to ensure not only that the law is implemented, but that there are the means of support available for former slaves and their children to live their lives in freedom and independence," the group's Africa programme officer, Romana Cacchioli, said before the ceremony was cancelled.

According to a local anti-slavery organisation, Timidria, males slaves are forced to work in farms and tender cattle, while women are confined to domestic duties.

Acting under pressure, Niger's parliament banned the keeping or trading in slaves in May 2003.

In a ceremony in December 2003, dozens of slaves were liberated, many of them shedding tears of joy as they were given certificates showing they were free.

That's 2003, not 1803.

Then there's this :

Assibit, 50, describes life as a slave in Niger, where 43,000 people are estimated to be in bonded labour, as the Timidria organisation which helped her escape wins an award in London.
[...]
Assibit was born into slavery - as was her mother, her husband and her five children.

The government says it is trying to clamp down on slavery - and has introduced laws so that slave owners can be punished - but still there are estimated to be tens of thousands of people in Niger in bonded labour.

That's from the 3rd of November, 2004. Not 1804.

But the problem isn't confined to "Deepest, Darkest Africa". Here's some testimony before the US Congress, Dated March 9th, 2005. :

At the job agent’s office in Beirut, my passport is taken away. The agency staff makes me stand in line with a group of women in the same predicament as me. Lebanese men and women pace in front of us, examining our bodies as if we were vacuum cleaners. I am sold to a wealthy woman, who takes me home to her mansion up on the forth floor of a condo building.

My chores seem unending. I wash the windows, walls, and bathrooms. I shampoo carpets, polish floors, and clean furniture. After twenty hours I am still not done. There’s no food on my plate for dinner, so I scavenge through the trash. I try to call the job agency, but the woman who now owns me has locked the telephone. I try to flee the apartment, but she has locked the door.

I can feel the burning on my cheeks as she slaps me. It is night and her kids have gone to sleep. Grasping me by the hair, she bangs my head into the wall and throws me to the floor. She kicks me and hits me with a broom. If I scream or fight back, she will kill me. So I bite my lips to bare the pain and then I pass out. This is my daily routine, the life of a slave.

And from the UK Telegraph :

As though time had turned back at least a century, tribal raiders are swooping on the villages of eastern Congo and carrying off their human booty to slave camps where order is enforced with beatings and amputations.

They come in the cool hours before dawn, their presence announced by the clanging of a cow bell that echoes through the hillside hamlets of the Hema tribe, overlooking Lake Albert in Congo's Ituri district.

Armed with machetes and machineguns, the raiders scythe through the rows of huts, torching their thatched roofs.

Mothers clutching their screaming children run through the flames into the arms of their captors, members of a militia from the rival Lendu tribe.

The fat and the elderly, those unsuited for work on the Lendu farms or in the gold and mineral mines they illegally occupy, are hacked to death.
[...]
The United Nations peacekeeping force MONUC recently managed to secure the release of 3,000 slaves after threatening military action against the militiamen holding them.
[...]
A little further down the fetid alleyway dividing the line of shelters in Tchomia, Francoise Ndroza is engaged in a similar battle to save the life of her four-month-old son Dieu, ill with acute diarrhoea. She too managed to escape the camp, where she was used as a sex slave - repeatedly raped by her captors on a daily basis.

When she tried to resist they drove a large pestle into her wrist, shattering the bones.

Leopold's regime was ended by outrage in Britain and America. Authors such as Mark Twain and Joseph Conrad, whose novel Heart of Darkness was a fictional account of the horrors of Leopold's Congo, joined the campaign. This time the world has offered little condemnation of the foreign businessmen and local militiamen whose greed to exploit Congo's natural wealth has fuelled a war more deadly than any other since 1945.

And from the Scotsman :

Nigerian police found more than 60 children packed into a shipping container in Lagos, and a police said it was believed they were to be sold as slaves or servants.

A woman accompanying the children was arrested after the discovery of the 60-70 boys and girls aged five to 14 yesterday.