Gangmasters make people work many hours and for low pay.
This work is often in factories or farms.
Or even in the sex trade.
Gangmasters took the Chinese workers to Morecambe Bay by the sea.
Here they collected shellfish from the sand.
This involved digging up these small sea creatures.
Workers had to bend over for hours to collect the shellfish.
One of these workers was Guo Bing Long.
He was twenty-eight years old.
The work was very hard.
But he thought of his family back home.
So he continued to work.
Usually shellfish collectors start work early.
This is when the water current or tide goes out.
The water flows away from the land.
And people can walk on the sand.
It is the best time to find the shellfish.
And shellfish collectors stop working before the tide comes in.
If they do not leave in time, there is a danger of drowning.
The water can rise very quickly.
But Guo Bing Long and his group worked late.
Their gangmaster, Lin Lang Ren, made them work dangerous hours.
On the fifth of February 2004 a tragic event happened.
Guo Bing Long was digging for shellfish.
It was late at night.
Suddenly the water started to come in.
It happened very quickly.
Guo was afraid.
He was trapped by the water current.
He needed help.
But he did not know who to call.
He used his mobile telephone to call his wife in China.
He said: “I am in great danger.
I am up to my chest in water.
Maybe I am going to die.
Tell the family to pray for me.
The water is too close.
I am dying.”
Guo Bing Long drowned in the water and moving sands.
21 other people drowned too.
And two other people are still missing.
No-one found their bodies.