At least 25 migrants were found stowed away on a cargo ferry bound for Britain shortly after it left the Netherlands.

Police stopped the vessel and quickly returned it to the Dutch port of Vlaardingen, emergency services in the Netherlands said.

Officers have not confirmed on the condition of the migrants, who were discovered on a Britannia Seaways ferry.

Ambulances were seen arriving in the port after the vessel returned on Tuesday afternoon.

Gert Jakobsen, vice president of communications with the ship’s operator DFDS, said the migrants were found after they made a hole in the trailer.

The roll on, roll off ferry was not far off the Dutch coast en route to Felixtowe, Suffolk, when the discovery was made at around 5pm on Tuesday.

Mr Jacobsen said police were waiting at the port and the migrants were taken to hospital by ambulance to check for hypothermia.

‘We don’t know about the checks. Of course, they were not in a very good condition,’ he said.

‘Unfortunately this is not the first time we have had such a situation. Of course, it’s rare they hide in a refrigerated trailer. But we do find migrants even though we try to prevent it.’

It comes weeks after the bodies of 39 Vietnamese migrants were found in a refrigerated lorry container in Essex after arriving on a ferry from Zeebrugge, Belgium

Officers detained the man on suspicion of assisting unlawful immigration on the A14 in Cambridge shire.

They stopped the vehicle near Brampton Hut, west of Huntingdon, today following reports of concern for the people inside.

The vehicle had been travelling westbound on the road when the force was called just after midday.

It follows the discovery of 39 bodies in the back of a refrigerated lorry in Grays, Essex, last month.

The victims were Vietnamese migrants and the vehicle’s driver, Maurice Robinson, faces charges of manslaughter relating to each one.