Talks have opened between Dutch, Belgian and British officials to try to prevent the ferry ports at the Hook of Holland and Zeebrugge becoming the new flashpoints for migrants attempting to enter the UK – now that security has been tightened substantially at Calais.

Dutch military police have been stationed at the Hook of Holland, near Rotterdam, since June, when 68 people, including two pregnant women and 15 children, were found locked in four cargo containers that had been shipped from the Netherlands to the English port of Harwich.

There are also regular attempts to enter the UK from Zeebrugge in Belgium, but the route from the Hook of Holland to Harwich is already known for its “carousel system” – where migrants found attempting to enter Britain are deported back to the Netherlands, before trying again.

Although June’s discovery of 68 stowaways – 35 from Afghanistan, 22 from China, 10 from Vietnam and one from Russia – was the largest to date, there have also been many others detained in recent months, including 18 Afghans found on a ferry, and nine Albanians in a lorry waiting to board.

Risk of accidents

That warning was echoed in the UK at the weekend by Keith Vaz, chair of the House of Commons home affairs select committee, who said that unless large-scale migrations were tackled at source, closing one route would simply have “a domino effect”.

“There is already evidence of more illegal activity around the Hook of Holland and Zeebrugge,” he said.

“We need agreements with countries across the north coast . . . before we see Calais-like crises springing up at ports right along the continent.”

Police say that in the first six months of this year, 220 migrants were caught trying to make the crossing from the Hook of Holland – though it’s not known how many were successful.

In the Netherlands itself, the number of asylum applications has doubled since the start of the year to between 500 and 600 a week, placing settlement services under severe pressure.

As many as 40,000 migrants are expected to apply for Dutch visas this year, up 25 per cent on 2014 – and the largest number since 1994, when 53,000 people applied, many of them displaced by the wars in Yugoslavia.