Border Force officers searched the vehicle acting on information from the National Crime Agency (credit: National Crime Agency)
The raids were instigated by the National Crime Agency following the discovery of 13 migrants, including one child, found in a cattle truck in the port of Calais on Saturday evening.
Border Force officers searched the vehicle, acting on information from the NCA who were carrying out investigations into a crime group.
The British national lorry driver, was detained by the French authorities. He remains in custody.
The other four men, arrested by the NCA, were questioned and later released under investigation.
Investigators also searched properties in Grays, Essex, and Worthing, West Sussex. At one a substantial amount of cash, thought to be around £100,000, was recovered and seized.
NCA regional head of investigation, Gerry McLean said: “Those who seek to profit from facilitating illegal immigration into the United Kingdom do so for their own selfish greed and without any concern for the health and wellbeing of those who are often moved across borders in inhuman and degrading conditions.
“We are determined to do all we can with our law enforcement partners to disrupt those networks and bring perpetrators to justice.”
The investigation is ongoing.
Tags: Grays, Thurrock, Romford, Havering, Brentwood