Boris Johnson has called the journeys “very bad and stupid and dangerous and criminal”, while a former royal marine has been put in the new post of “clandestine Channel threat commander”.
Priti Patel, the home secretary, called crossings “totally unacceptable” and government statements have repeatedly labelled them illegal.
Anne McLaughlin, co-chair of the All-Party Parliamentary Group (APPG) on Refugees, told The Independent it was “not illegal for people to cross the Channel” using irregular routes.
“The language seems very deliberate and ideological about views that people need to be seen as not human, but criminal,” she added.
“I don’t believe for a minute that they’re not aware that using language like ‘Channel threat commander’ will make the public see people as a threat.”
The Scottish National Party MP called the prime minister’s comments on “dangerous and criminal” crossings “vile”, adding: “It’s intended to sow division.
“As far as I can see, what the government is concerned about is building walls to stop people getting into the Channel and not about tackling the root causes,” she added.
David Simmonds, the Conservative co-chair of the APPG on Refugees, urged the government to bolster “robust legal routes” to seek asylum in order to bring the situation under control.
“The existing routes are not robust enough,” he said, warning that although crossings will decrease when the weather worsens the demand will not.
Mr Simmonds said “a lot” of migrants had already died attempting to reach the UK and the true number is unknown.
“We have no idea at the moment how many people have been lost in the Channel but historically we know that people have drowned and their bodies have never been discovered,” he added.
More than 4,000 migrants are believed to have arrived in the UK using small boats so far this year, following a dramatic increase in crossings since 2018.
As more people arrived on Wednesday, the mayor of Calais said that sending royal navy ships into the Channel would be a “declaration of maritime war”.
“The British government should take care of its own responsibilities,” she added. “We in Calais no longer want to be permanent hostages enduring the lectures of British leaders.”
Laura Padoan, a spokesperson for the UN Refugee Agency (UNHCR), said the response to Channel crossings had become “immensely charged” despite the UK receiving far fewer asylum applications than other European countries, including Germany and France.
According to UNHCR figures, the number of refugees resident in the UK fell from 238,000 to 133,000 between 2009 and 2019.
“It’s not a crisis, it is manageable,” Ms Padoan told The Independent. “For people crossing the Channel, saving lives should be the first priority – both on sea and on land.
“Rather than using large naval boats to block flimsy dinghies and potentially create more dangerous conditions, efforts should be stepped up to increase search and rescue operations and to combat smuggling rings.
“We should respond with humanity rather than hyperbole.”
An official UNHCR document on terminology states that the term “illegal migrant” is legally incorrect and “dehumanising”, adding: “The word ‘illegal’ depicts migrants as dishonest, undeserving, and criminals who are a threat to the public good.
“This normalises the use of punitive measures, enforcement, and procedures to punish and deter irregular migrants."
The Refugee Council said the term “illegal migrants” should not be used to describe vulnerable people seeking safety and protection.
Its director of advocacy Lisa Doyle said: “This unhelpful language can stoke tension and division, at a time when we need the government to show strong, compassionate and responsible leadership on asylum policy.”
The Joint Council for the Welfare of Immigrants said the continued use of the word “illegal” was “dehumanising, wrong, and seems calculated to whip up anti-migrant sentiment”.
Its legal policy director Chai Patel added: “People have a legal right to cross borders without documents in order to seek asylum.
“No human being is illegal, and this language wrongly leads to a perception that migrants should be prosecuted and punished, instead of treated with the dignity and respect everyone deserves.”
Charity Refugee Action accused the government of “overt and aggressive hostility” towards asylum seekers crossing the channel by boat.
“It is making a bad situation dramatically worse,” said chief executive Stephen Hale.
“Their language shows no understanding and no compassion for people who have come from violent and oppressive countries and suffered in ways that are beyond many of our imaginations.
“This language is also certain to exacerbate the anxiety felt by many people already in the UK who have claimed asylum, and to give cover to those who may wish them harm.”
Extremist group Britain First has launched a “patrol boat” in the Channel and far-right activists have been harassing migrants at a reception centre in Dover.
A Home Office spokesperson said the word threat, in the title “clandestine Channel threat commander”, was an “operational term that can refer to anything that can compromise the integrity of the border”.
She denied that the government was calling migrants a threat.
A Foreign Office document said that “illegal” and “irregular” migration were considered to be distinct terms by the government, with the former involving people-smuggling and organised criminal gangs.
It called the UK “one of the world’s leading refugee resettlement states” and said a new global scheme would be open to asylum seekers from any country, rather than just Syria.
An official report by parliament’s Foreign Affairs Committee warned in November that government policies were “driving migrants to take more dangerous routes, and pushing them into the hands of criminal groups”.
MPs warned that spending millions of pounds on security around key French ports had caused an increase in numbers trying to cross the Channel in small boats, and that the government should instead increase legal routes to seek asylum and address the root causes of migration.