More than 37,000 attempts made by migrants to enter the UK via the Channel Tunnel have been blocked so far this year, according to Eurotunnel.
The statement comes after two successive nights of mass attempts to breach the tunnel by some of the thousands of migrants camped in northern France, hoping to reach a better life in the United Kingdom.
The company has come under increasing pressure to demonstrate its efforts to police the tunnel, which is a major conduit for both cargo and passengers between France and the UK.
For the most part, migrants caught trying to enter the tunnel are released almost immediately. Their camps hold about 3,000 people.
Migrants attempting to storm the Eurotunnel in Calais are making the journey from their camps on foot, before waiting for darkness to break through fences, a Eurotunnel spokesman said.
Once the fences have been breached, they make their way onto the platforms and try to hide on lorries or freight trains, in order to make it into the UK undetected.
Eurotunnel spokesman John Keefe, said: "They feel that have got a better chance of hiding in the dark or escaping undetected.
"Searching the trains can take a very long time, and this could mean significant delays being caused to freight services.
"It is freight services, not passenger services that are being affected. The two run on separate parts of the terminal."
Mr Keefe added that the migrants can be seen approaching the terminal during the day - having made the four to five kilometre journey from their camps on foot - and then waiting on public land for night to fall.
He continued: "They position themselves around the terminal, on public land, and then when it becomes dark start to try and come through the fences.
"On Monday night, into Tuesday morning, there were a number of migrants who were successful in crossing the channel into the UK.
"We stopped them and informed the authorities."
Speaking of last night's incident, he said that none of the 1,500 people were successful in crossing the channel.
"Last night we had another large scale incursion by migrants. The number is around 1,500 who were prevented from crossing the channel and removed by French police.
"They were found trying to break in through the fences on or around the freight platform.
"Unfortunately, last night there was another death, and it appears that the migrant was run over by a truck. But we don't know the circumstances of how that happened."
Mr Keefe said that migrants are not getting "anywhere near" the tunnel itself, and that the disruption is being caused on the platforms.
"They go to the the platform area and the try to get into either trucks or trains directly, in that area and hope to get a ride into the UK.
"When they come through the fences we then send patrols to pick them up.
"They make their way to the platforms, the platforms are secured by large numbers of security personnel and police forces, and they are removed from that area and put on to buses by police.
"When there are hundreds, that simple process takes all night," said Mr Keefe.