Irregular migration to the UK "is increasing", an anti-trafficking expert said.
Andy Desmond, Director of Anti-Trafficking Consultants, told Good Morning Britain that the hot weather simply makes cases, such as those of migrants in lorries, "more overt because of their own distress."
Following the discovery of 35 Afghan Sikhs in a shipping container at Tilbury Docks at the weekend, a lorry has been discovered carrying 15 migrants with suspected dehydration in Somerset. The German driver has been arrested.
More top news
The RSPCA are trying to find who is responsible for leaving the trap out as they are warning they could be breaking the law.
Fine start to the week for most but turning wet and windy from Wednesday.
Thousands of people have lined the banks of the Mersey to see Cunard's three flagship ocean liners sail down the river.