Twelve suspected illegal immigrants thought to be from Nigeria have been arrested following a raid on a scrap metal yard in Dartford.
Kent Police and officers from the UK Border Agency raided A2 Car Breakers in Watling Street earlier.
The operation followed an inquiry which took several months.
The site, which contained about 2,000 vehicles, is bordered by Watling Street and the A2. A temporary road speed restriction was imposed on the A2.
Police said the aim was to ensure the safety of anyone trying to escape across the coastbound carriageway.
Sgt Tim Ryton said: "Despite this being a large site, we were quickly able to contain it and prevent those there from leaving."
The arrested men, who claimed to be from Nigeria, are now in the hands of the UK Border Agency.
Spokeswoman Karyn Dunning said the agency would work towards removing them from the UK as soon as possible.
The raid at the breakers' yard was supported by Kent Trading Standards, Dartford Borough Council and a police helicopter.