There are several large migrant camps in forests, in car parks and in abandoned industrial areas along the French coast towards the canal.
- We estimate that there are about 1,000 people here right now, but it is impossible to know because it changes from day to day, says Andy Brown, volunteer worker in the French city of Calais.
- Everyone here wants to go to England. 20 of my friends went yesterday and I will go soon, says one of the migrants.
Where the strait is narrowest, the distance is just over 30 km. But large vessels run in the fairway at the same time and it is one of the world's busiest routes.
- Many are desperate. A majority want to go to the UK because they have relatives there, says volunteer Andy Brown.
Another aspect that several migrants we meet themselves highlight is that the UK no longer belongs to the EU. They say this will make it harder for the country to send them back once they get there.
The increased flow of migrants has raised the mood between the countries. The British Home Secretary has said the situation is "unacceptable" and has called for action by France.
The British government has also recently announced plans to deploy military vessels as a barrier to migrants.
"This very dangerous route must be made unaffordable," said Priti Patel, Britain's Home Secretary.
Thousands have tried to cross the straitIn total, more than 4,500 migrants have so far this year been exposed crossing the strait.
- Compare that with the number of people who have come to Scandinavia, Germany or Italy, says Andy Brown.
They say it's unacceptable?
- I will talk about what is unacceptable. It is that 15-year-old children sleep in the ditches in Calais, says Andy Brown.