The British government decided to add an extra 300 meters of wall in Calais along the roads of a port to avoid the “invasion of migrants,” AFP reported.

"The objective is to add an extra 300 meters to the fences that have already been installed," Vincent Berton, Deputy Prefect of Calais, told the source.

The key thing is to build the fence to deter refugees from hoping into cargo trucks heading from Calais to Britain, while at the same time not interfere with the smooth flow of traffic, which is essential for the economy of the city, Berton explained.

Calais' port director, Jean-Marc Puissesseau, emphasized that the traffic of the port can't be affected by the construction of the wall.

"We can't continue to lose sales because of migrant business!" — Puissesseau said, as cited by AFP.

The wall will be four meters high and have police officers on duty at certain spots to prevent the refugees from climbing over the fence.

Although the wall will be built in France, the British government will fund the project, AFP said.

The project should start "before the end of May" and be completed "before the summer." The cost of building is expected to be around 8 million euros ($9 million).

According to AFP, there are currently between 3,500 — 5,000 refugees living in Calais and its surrounding areas, hoping to reach Britain.