Aid organisations said migrants camped in Calais had made last-ditch attempts to cross the Channel ahead of today's operation.
Border police were said to have spotted groups of up to 40 people hiding in bushes along roads leading to the port.
Some were attempting to jump on lorries as they slowed down.
More top news
Climate change is a pressing issue for Tonga, but has it had the attention it deserves at the Commonwealth summit?
With temperatures peaking at 29C today, it is the hottest April day for nearly 70 years.
Russian trolls are behind a disinformation campaign about chemical weapons attacks in Syria and Salisbury, a government source has said.