Enforcement teams have been conducting raids in nail bars and convenience stores suspected of employing people illegally across south Wales as part of Operation Tornado - a national initiative to tackle illegal employment.
When the uniformed officers visit other premises, it is a similar scene to the one in Port Talbot - people quickly whip off their masks and pretend they are not working there, while businesses deny employing them.
The Home Office said it had ramped up these UK-wide raids this year, carrying out 3,188 visits with 2,299 arrests between 5 July and 31 October 2024 - there were 2,371 visits with 1,836 arrests for the same period in 2023.
"If an employer hires an illegal worker now they can get fined £45,000 for every illegal worker and if they offend again it could be £60,000," said Mr Johnson.
During the week of Operation Tornado penalties worth up to £4m were issued to more than 50 businesses.
However these hefty fines are not deterring everyone.
Many businesses are on high alert, with posts on Vietnamese Facebook groups issuing warnings about raids. Others offer services to keep a look out for officers.
"The Home Office and taxmen have been checking around Cardiff. Everyone, immediately avoid the area," one post read.