Eighteen suspected illegal immigrants have been arrested after a lorry was stopped on the M1 in Hertfordshire.
A motorist called police after following a "suspicious" lorry on the M25 on Saturday.
It was later stopped close to junction 9 of the M1 near St Albans and 18 men claiming to be from Vietnam were found.
They were arrested on suspicion of illegal entry to the UK and the driver, a man aged 40, from Poland, was held for assisting entry.
"Eighteen people who are believed to have entered the UK illegally on the lorry were taken into custody for their safety.
"The driver of the lorry, a 40-year-old man from Poland has been arrested on suspicion of assisting people entering the UK unlawfully," a spokesman said.