Police stopped more than 80 vehicles - and made four arrests - during an operation targeting human trafficking and modern slavery in Hertfordshire.
The six-hour crackdown, involving more than 100 police officers, targeted vehicles crossing the border between Hertfordshire and London and immigration and vehicle safety checks were carried out.
In total, 83 vehicles were stopped by police and 67 people were spoken to about modern slavery and human trafficking.
Three potential victims of slavery or trafficking were identified and supported by the Red Cross.
Four people were arrested on suspicion of offences including theft, theft of a motor vehicle, possessing drugs, driving while disqualified, carrying a knife and drug driving.
One person was cautioned for possessing cannabis and one suspected stolen vehicle was recovered.
Five uninsured vehicles were taken off the road and seized as well as others with mechanical defects. Other driving offences such as speeding and not having an MOT were also dealt with.