Five suspected people smugglers have been arrested after 27 migrants drowned trying to cross the English Channel.
Seventeen men, seven women, including one who was pregnant, two teenage boys and a young girl died after their boat capsized near Calais on Wednesday afternoon.
The two survivors are from Iraq and Somalia, while the inflatable boat they travelled in was bought in Germany.
Five suspects have been arrested in France, where Interior Minister Gerard Darmanin has criticised the UK’s handling of the migrant crisis, describing it as an “international problem”.
Meanwhile President Emmanuel Macron has warned that tackling the issue at sea and on beaches is “already too late”.
Here Sky News looks at who the people smugglers organising Channel crossings are and how they operate.
Where do the migrants come from and why do they risk the Channel?
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So far this year an estimated 25,700 people have made the dangerous 25-mile journey across the English Channel to Britain.
They come from a range of countries, but most are from Iran, Iraq, Syria, and Afghanistan, as well as parts of sub-Saharan Africa such as Eritrea, Ethiopia, Sudan and South Sudan.
Others travel from Tajikistan, Turkey, Egypt, Yemen, Chad, Niger, Libya and Albania.
They are mostly fleeing oppression, conflict or deprivation in their home countries and are seeking a better life in Europe.
In recent years more and more people from politically unstable countries have realised they have a right to asylum elsewhere.
“Increasingly people are recognising they have refugee status and are entitled to and need asylum in another country,” Steve Valdez-Symonds, UK refugee and migrant rights director for Amnesty International, tells Sky News.
Some may already have friends and relatives who have made similar journeys and will aim for specific countries to settle in.
But others “will go wherever they can”, Robin Jenkins, founder of international rescue boat charity Atlantic Pacific, says.
“The impression a lot of people have of refugees is that they have strategically planned-out journeys.
“Some will do more research than others and go for places where they know people already.
“But some will go wherever they can – to the next safest place – and that’s where people exploit them.”
Who are the smugglers?
People smugglers are different to human traffickers – although both involve organised crime groups (OCGs).
Smugglers only facilitate people travelling illegally between countries, but traffickers move people across the world by force and involve them in slave labour, exploitation, or abuse.
Throughout the long journey from a migrant’s country of origin to their destination, smugglers may use and pay traffickers to do things for them – such as bribe border officials or use a safe house.
The smugglers themselves can often be found in the region migrants are fleeing from.
“When someone needs to flee their home country, they will seek someone – a friend, relative or other contact – who knows someone who can smuggle them out,” Mr Valdez-Symonds, of Amnesty International, says.
“That introduces them to a whole series of potential networks – some which will help them – others which will exploit them – and some which do both.”
Many use social media, including WhatsApp groups, to find smuggling networks.
In Iraq, Sky News Middle East correspondent Alistair Bunkall spoke to a local smuggler.
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Giving a fake name and using hundreds of sim cards on an untraceable burner phone, he charges Iraqis who want to flee to Europe – and makes $100,000 (£75,000) a year.
“We collect and transport people to the UK via Dunkirk,” he says. “Where we put them on boats.”
Colin Carswell, a retired Met Police superintendent of 30 years, who led the first Joint Investigation Team on human trafficking in Europe, says smugglers can charge migrants between $3,000 (£2,250) and $30,000 (£22,500).
“The commercial process behind the business of people smuggling is no different to any other,” he says.
“In places like Iraqi Kurdistan, people will be presented with a story and a price of how much it will cost.
“Sometimes all the money is paid up front, other times it’ll be once they’ve got there.”
Migrants often nominate a friend or relative back home to pay on their behalf, who can be used by gangs as a means of extortion, he adds.
“Sometimes they’ll go back on their word and demand more money, which is particularly common with people going through sub-Saharan Africa.
Mr Jenkins, of Atlantic Pacific, tells Sky News he has heard “unrepeatable” stories of people being tortured for money in countries like Libya.
Which routes do they take?
Although there are countless routes of migration into Europe, smugglers largely operate around three main ones.
Which one they choose depends on who has arranged the journey and where the refugees are coming from – the Middle East, central Asia or sub-Saharan Africa.
“There’s no simple model,” Mr Carswell says. “But one particular OCG will have a route and they will have their own people or work with other people along that route.”
Refugees from the Middle East often travel through Turkey to the western city of Izmir, where they make the short journey by boat across the Aegean Sea to the Greek Islands.
Others go solely by land through the Balkans into countries such as Bulgaria and Albania, before making their way further across the continent.
Political tensions between the EU and Belarus have seen a new route open up there in recent months.
In response to European sanctions over last year’s elections, President Alexander Lukashenko is thought to be granting refugees tourist visas before encouraging them to enter the EU via Poland, Latvia or Lithuania.
“Gangs are resilient,” Mr Carswell says. “They will change their methods depending on countries’ political positions and divert their routes.
“That’s what we’re seeing in Belarus.”
Migrants from Sudan, South Sudan, Ethiopia, Eritrea, Chad, Niger and the Central African Republic have no choice but to cross the Sahara in the hope of making it to the Mediterranean coast.
“It’s a huge expanse, which is a hugely hostile and unforgiving place,” rescue charity founder Mr Jenkins explains. “Lots of people die there.”
Many from elsewhere are promised job opportunities in Libya, but when they reach there “the reality is totally different”, Mr Jenkins adds.
If they’re able to, they continue to Morocco where they can cross into Western Europe via Spain.
How do they make it across the Channel?
Once migrants make it to Western Europe, people smugglers have numerous ways of getting them to the French border.
On rare occasions they use fake or stolen passports to fly people across countries, but usually they transport them by road.
Smugglers also use safe houses or camps to transit large groups of people to the French coast.
“At that point they can be there for hours, days or even weeks, before they are moved on again, by train, lorry or even on foot, hundreds of miles further,” Mr Carswell says.
The boats used in Channel crossings are usually just inflatable dinghies.
They are often bought from online retailers, some as far away as China, or dealers in neighbouring countries such as Germany and the Netherlands.
A Sky News investigation traced one used for a migrant crossing on 20 July this year to a dealership in Rotterdam.
Mr Jenkins, whose charity rescues people in the water, says: “I wouldn’t put them on a lake let alone an ocean. They are terrifyingly badly made.”
The boat used in the crossing that killed 27 on Wednesday was described by the French interior minister as “very frail” and “like a pool you blow up in your garden”.
Often the steers are taken out to fit more people on board, the engines are too small, and there isn’t enough fuel to cover the whole journey.
As there are more patrols in the daytime, migrants are instructed to meet at a hidden point on a French beach at night.
There they are told how to use the boat, which often ends up carrying double the number of people promised.
Mr Valdez-Symonds explains: “Smugglers don’t put their lives at risk by setting off in a tiny boat that isn’t seaworthy.
“They may nominate someone as the person in charge, but that’s usually the limit of their engagement.”
Sky News Europe correspondent Adam Parsons accompanied a French border patrol earlier this year.
He described the “jet black” sea as “like a vast pool of ink”.
As dinghies are made of plastic, they are hard to detect by radar and often even the most experienced seamen aren’t able to see “laden dinghies until a few metres away”, he said.
The majority of these small boats are intercepted by British or French border patrols or rescue charities. They are then brought ashore on either side and around 98% begin the process of seeking asylum.
Can police catch them?
With three times the number of migrants attempting to cross the Channel this year than last, Prime Minister Boris Johnson and Home Secretary Priti Patel have repeatedly promised to step up patrols and intelligence gathering.
But the French authorities have criticised Britain’s handling of the crisis, including so-called ‘push back tactics’, which see boats forcibly turned back to France.
Although border forces on both sides use sea, land and air patrols, French President Emmanuel Macron has warned that stopping people on beaches is “already too late”.
“If the UK wants to stop the boats from coming, it needs to stop the gangs,” Mr Carswell says.
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“And the gangs that are responsible for this are within Europe.”
But now the UK is no longer part of the EU, sharing intelligence on smuggling networks with Europe is “significantly harder”, he claims.
“It is significantly more challenging because of Brexit – as we are out of Europol.
“In this latest case, there will likely be a Joint Investigation between France and Germany that will involve Europol.
“But we won’t automatically be part of that – because now we’re not in the EU we have to be invited to join.”
He says that although the UK can no longer initiate a Joint Investigation Team, this week’s deaths will likely “accelerate political cooperation”.
“Where joint interests align like this, there will be no difficulties. But people shouldn’t have to die before something is done,” he says.
The JIT Mr Carswell led on human trafficking in 2007 “lasted three years” and was “very complex”, he adds.
“There needs to be a range of measures. The short-term might have to be patrols on French beaches and turning boats around in the Channel. But the medium term has to be political.”
Mr Jenkins adds: “The quickest and easiest way to resolve this is to provide safe passage, so people don’t have to turn to smugglers.”