By Dulcie Lee
BBC Newsnight: Lewis Goodall reports from Dunkirk's new migrant camp.
The UK is determined to smash the "evil" business model of people traffickers, an immigration minister has said, after 27 people drowned crossing the Channel on Wednesday.
Kevin Foster said the UK, France and rest of Europe must tackle the problem together, following the biggest single loss of life in the Channel on record.
A fifth person has been arrested in connection with the fatal crossing.
Five women and a girl were among the dead, France's interior minister said.
Gerald Darmanin also said two people had been rescued and one was missing.
It was earlier reported 31 people had died, but the total was revised down overnight into Thursday.
Mr Foster told BBC Breakfast ruthless criminals were sending people into the Channel's dangerous waters on flimsy boats without proper equipment.
"Those who organised that boat yesterday would have just viewed these people... who passed away, as just a profit-making opportunity," he said.
The alarm was raised on Wednesday after a fishing boat crew spotted several people in the sea off the coast of France.
The International Organization for Migration said it was the worst single loss of life in the Channel since it began collecting data in 2014.
Speaking from Downing Street, PM Boris Johnson 'shocked and saddened' at migrant deaths
Boris Johnson said he was "appalled" by the tragedy, adding the UK would leave "no stone unturned" to stop human trafficking gangs.
The UK prime minister said on Wednesday that while the UK and France had agreed more needed to be done, there had been "difficulties" persuading the French "to do things in a way that we think the situation deserves".
Speaking after an emergency government Cobra meeting on Wednesday, Mr Johnson said it was clear French attempts to stop the migrant boats leaving "haven't been enough".
He said he hoped the French would find a renewed offer of joint patrols along the French Channel coast "acceptable".
Meanwhile, French officials said Mr Macron had told Mr Johnson "he was expecting the British to co-operate fully, and that they abstain from instrumentalizing a tragic situation for political purposes".
The UK has pledged to pay France €62.7m (£54m) during 2021-22 to help increase police patrols along its coastline, boost aerial surveillance and increase security infrastructure at ports.
By Simon Jones, BBC News reporter in Dover
Despite yesterday's deaths in the Channel, the crossings have continued this morning. Around 40 migrants have been brought to Dover by the lifeboat charity the RNLI.
It's windy on the water and extremely cold - but the determination to get to the UK remains as strong as ever.
The task is now under way to establish the identities of the people who died. That may prove problematic, as many migrants take to the water without any paperwork.
Another key concern is why their boat sank - was it overloaded, was the sea too rough, or could it have been hit by a passing ship?
The French authorities have described the boat as very flimsy.
In previous years, crossings tend to fall dramatically in autumn. That hasn't happened this year.
That's because the route has become so lucrative for the people smugglers who charge migrants around £3,000 each to get on a boat.
Mr Macron said France would not let the Channel become a "cemetery". Since the start of 2021, he said, 1,552 smugglers had been arrested in northern France and 44 smuggler networks dismantled.
Despite this, 47,000 attempted Channel crossings to the UK took place this year and 7,800 migrants rescued, Mr Macron added.
Home Secretary Priti Patel will speak to her French counterpart later to discuss their response to the tragedy.
A number of people are believed to have reached the UK in small boats on Wednesday, with people seen being brought ashore in Dover by immigration officials.
It comes amid record numbers of migrants making the crossing from France to the UK.
The Dover Strait is the busiest shipping lane in the world and has claimed many lives of people trying to cross in inflatable dinghies.
It is thought at least 10 other people had died in the past few weeks while attempting to make it.
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