Four people have been arrested and charged with involuntary manslaughter in France following the fatal sinking of a migrant boat in the Channel.

Six men died after the vessel they were aboard got into difficulty near Calais on Saturday.

More than 50 other people were rescued by French and British coastguards.

French judges are also reportedly considering further charges against the Iraqi and Sudanese suspects.

At least two of those detained are thought to have links to human trafficking networks, according to French media.

The people on board were reported to be mainly Afghan, with some Sudanese also present.

Karim was one of about 10 people who was turned away from boarding the vessel due to overcrowding, despite paying people smugglers €2,000 ($2,200; £1,700) for a place.

He told the BBC the smugglers promised him a “good boat” – something at least 10m (32ft) long – but what they were given was only 3m long.

Two of his friends were allowed aboard and Karim thinks they were among those who died.

Another man, Idris, managed to survive the journey but has ended up back in France.

“There were far too many passengers,” the 22-year-old told the Reuters news agency.

“The waves were very strong, and the boat split up.

“Half the passengers fell into the water and were swallowed up by the sea. Those who were left in the boat tried to stay alive with the help of their lifebuoys.”

Rescue workers on Saturday said it was the seventh time that week that they had pulled people from the water, raising concerns that the smugglers organising the crossings may be using a defective batch of boats.

The English Channel is one of the busiest shipping lanes in the world, with 600 tankers and 200 ferries passing through it every day.

Despite this, many people are willing to take the risk.

Figures released on Thursday show more than 17,000 migrants have arrived in the UK so far this year after crossing the Channel.

More than 400 people arrived in small boats on Wednesday alone.

The BBC also spoke to Zhala in Calais, who said she was fleeing gun attacks in Iraq with her young family. They have repeatedly tried to get on a boat.

“It’s fate,” she said when asked what she thought about Saturday’s sinking.

“It’s not dangerous for us. We’ve come across so many difficulties in my country.”

A migrant from South Sudan, who has set up a camp hidden in the bushes on the coastline, told the BBC he was adamant to get to the UK to make a success of himself.

He said: “[The UK} colonised me in Sudan, that’s why. It’s like my father.”

Explaining why he wants to leave Sudan, he explained he was leaving because of war and corruption.

But French authorities have threatened to move him and his fellow countryman from their makeshift camp, he added.

Karim said he is also still looking to try and make it across into the UK.

Aid workers in Calais say more migrants have been arriving in recent weeks and have been living rough on the coastline. They say many of them are determined to get to the UK, despite warnings over the dangers of the crossing.