­­­­­­The chances of there being no sleeper terrorist among the thousands of migrants arriving in the UK by small boats is “nil”, it has been warned in Parliament.

The danger to UK security posed by the Channel crossings was raised at Westminster by former Labour MP Baroness Hoey.

The non-affiliated peer also argued if action had been taken sooner to tackle the small boat problem, this week’s tragedy may have been avoided. At least 27 people, including pregnant women and children, died when a dinghy capsized off the coast of Calais.

She described it as a “wake-up call, much too late”.

But her comments about the security risk posed by the migrant crossings were rejected by refugee campaigner and Labour peer Lord Dubs, who warned they were “damaging” and “the most awful accusation to make against our fellow human beings who are fleeing for safety”.

Opening the debate she had secured in the House of Lords, Lady Hoey said: “The terrible tragic loss of at least 27 people should shock us all.”

Pointing out that more than 23,000 people had made the perilous journey across the Channel in small boats so far this year, she said: “It is a fact that 98% of those arriving will claim they are asylum seekers and most have no papers to show where they come from or are told by the smugglers to destroy their documents. That in itself is, I believe, is dangerous to our security.

“I am sure some of you will have seen that in Lithuania where they took in 4,000 people via Belarus they discovered that 24 of those people had direct links with Isis.

“So it doesn’t take much working out that with our much larger number the chances of there being no sleeping terrorist coming here is nil. And the Government’s first duty is, of course, to protect the safety and security of its citizens.”

She added: “We have to send a signal that we are not an open door and that we will not continue to allow the industry of lawyers making millions from the whole asylum-immigration system, mostly from legal aid paid for by the public.”

Urging “rigorous and determined action” to stop the boats coming, Lady Hoey said: “Yesterday’s tragedy was a wake-up call, much too late. We cannot go on like this or we will see other disasters even bigger in the future.”

But Lord Dubs, who fled the Nazis as a child on the Kindertransport scheme, said: “I do not see refugees coming here and fleeing for safety as a terrorist threat to this country.

“We are a country that’s traditionally had humanitarian principles. We are a country that’s had a sense of decency. We are a country that’s believed the vulnerable of this world, though suffering from persecution, are entitled to safety.”

He added: “Nothing can be more damaging than to say to local communities if you got somebody who’s fled the war in Syria, or fled from Iran or Iraq… ‘Watch that person because they are liable to kill you’. That is surely the most awful accusation to make against our fellow human beings who are fleeing for safety.”

Responding, Home Office minister Baroness Williams of Trafford said: “Security is number one for border control. All our processes and procedures are predicated on the need to safeguard the UK from those who pose a security threat.

“People arriving by small boats are subject to stringent checks immediately upon arrival in the UK and again as they are processed into the asylum system.”