A new record number of migrants crossing to UK shores shows that the Home Office has "lost control", it has been claimed.
At least 235 migrants made it across the dangerous waters of the English Channel on Thursday, taking advantage of calm weather.
It came amid speculation that the Royal Navy could be drafted in to patrol the busy shipping lanes if the high number of migrant crossings continues.
Thursday was the second time in just over a week that a new single-day record has been set, after 202 people crossed to the UK on July 30.
Human rights charity Detention Action has accused the Home Office of "fuelling chaos, criminality and untold trauma".
Meanwhile, Immigration Minister Chris Philp said he shares "the anger and frustration of the public" at the "appalling number" of crossings.
More migrants are also believed to have tried to reach the UK on Friday amid calm winds in Dover in the early morning.
Border Force vessels Seeker and Speedwell have been active in the Channel.
Thursday's new high mark for crossings involved 235 people arriving in the UK in 17 vessels.
In one incident, Border Force officers apprehended 15 migrants who had landed at Dungeness beach in Kent.
The Home Office has not yet provided a full breakdown of Thursday's crossings, and the total number could be higher still.
Detention Action director Bella Sankey said: "The Home Office has lost control and all credibility on this issue, fuelling chaos, criminality and untold trauma for those who feel forced to make these dangerous crossings.
"Trying to make this route 'unviable' through greater enforcement is naive grandstanding and amounts to more of the same.
"What is needed is recognition that people who reach France will have valid claims to protection in the UK and the urgent development of safe and legal routes for them to do so.
"This would end the crossings overnight and ensure we are standing by our age-old tradition of protecting those seeking sanctuary on our shores."
Her comments came amid speculation about a possible role for the Royal Navy in patrolling the Channel if migrant crossings continue at pace.
Chancellor Rishi Sunak has declined to deny reports that the Navy could be used to patrol the Channel for migrant crossings.
He told Sky News: "I think people are absolutely right to be frustrated at the scenes they're seeing. I'm frustrated, everyone is, which is why we've been working much more closely with the French government in recent time to improve our co-operation and intelligence-sharing to police crossings.
"The immigration minister will be visiting France again, I believe next week, to discuss how we can step up that co-operation and take further action, further measures and stronger measures as required to stop and reduce the tide of boats coming."
Asked about reports that the Navy will be used, he said: "I wouldn't want to speculate on exactly what measures will be put in place.
"It's important that we work closely with our French allies on this situation.
"Obviously France is a safe country for migrants to be. We all want to see these crossings reduced and, pending the outcomes of those conversations, we can decide on the best next steps to take."