Calais, France (CNN) Since the migrant crisis exploded in the summer of 2015, thousands have perished trying to cross the Mediterranean, with the death of three-year-old Syrian Alan Kurdi, whose body washed up on a Turkish beach, shocking the world.

But this year, more and more refugees are trying to cross a different stretch of water, the English Channel, one of the busiest shipping lanes on the planet, in hopelessly inadequate boats.

UK government figures show that more than 100 migrants have set out in small boats from France and made it into British waters since November 2. The French coastguard says it is now rescuing migrants from the English Channel every day.

On the outskirts of Dunkirk, northern France, hundreds of migrants, mainly Iranians but also Iraqi Kurds, sleep rough in a wood on a nature reserve, sandwiched between a lake on one side and a supermarket on the other.

Ahmed, an Iranian migrant in France who plans to cross the English Channel

The Iranian migrants say a combination of economic hardship and political persecution is driving them here in ever greater numbers. Their aim? To reach the UK, where they believe it will be easier to claim asylum. And they are hoping to get there soon, before Britain's scheduled departure from the European Union on March 29, 2019.

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