Reports on the BBC and in The Times claimed that the Navy is set to take charge of operations looking to limit crossings by asylum seekers in the Channel within weeks.
It has been claimed that the move is part of a raft of populist policies set to be published by Prime Minister Boris Johnson, dubbed Operation Red Meat, to save his leadership following a series of revelations linked to lockdown breaches.
Refugee charities have described the proposals, which could also see migrants sent to countries such as Ghana and Rwanda for processing and resettlement, as “inhumane”. Last year, 27 refugees drowned – among them three children and a pregnant woman – as they attempted to cross the English Channel in a small boat.
SNP Shadow Home Secretary, Stuart McDonald, said: “Reports that the Tory government intends to put the military in charge of targeting vulnerable refugees in rickety boats and send them to overseas detention facilities are utterly appalling.
"It is shameful that Boris Johnson is putting forward these toxic policies in a desperate attempt to woo his right-wing backbench MPs, distract from the scandals engulfing his party, and to save his own skin.
"The SNP has been consistently clear that the UK government must step up efforts to secure safe and legal routes for people fleeing hardship, poverty and conflict – including refugees from Afghanistan left behind after the UK's chaotic exit from the country.
"Instead, Boris Johnson and Priti Patel have ramped up anti-refugee rhetoric and lurched even further to the extremes.
"Despite the Channel crossing tragedies we have witnessed, it speaks volumes of how low this broken, scandal-ridden Tory government is willing to go to put its own interests first."
Defence Select Committee chairman Tobias Ellwood criticised the plans as "rushed" by the government and said they were a "massive distraction" for the navy.
Yvette Cooper MP, Labour’s Shadow Home Secretary, said: "The Government has failed to do the serious, practical work with France that is needed to stop lives being lost and criminal gangs profiting from dangerous Channel crossings. Instead, this looks like Boris Johnson is using the situation to chase headlines to distract from the total mess he is in as a result of rule breaking parties in Number 10.
“They've announced pushbacks that they’ve now admitted won’t work and keep re-announcing offshore processing even though no other country has agreed to it and it was incredibly costly and damaging when tried in Australia."
She added: “The Prime Minister should say whether this latest briefing means he has lost confidence in the Home Secretary and the Border Force or whether this is really about the crisis of confidence in him."
Home affairs spokesperson Alistair Carmichael said: "This is a blatant and desperate attempt by Boris Johnson to distract from stories about parties in Downing St during lockdown. This is as clear an example of the so-called “dead cat” strategy as we have ever seen but they are going to need a bigger cat. For the good of the country, Johnson should resign now.
"These Channel crossings need to stop, but the Conservatives’ approach clearly isn’t working. These crossings are incredibly dangerous – as demonstrated so tragically by the deaths of 27 people when their dinghy sank in November.”
He added: “The best way to prevent refugees from attempting these perilous journeys, and keep them out of the hands of people smugglers and human traffickers, is to provide safe and legal routes to sanctuary."
Westminster education secretary Nadhim Zahawi said the move would help avoid a situation where "Border Force or other vessels in the channel are being co-ordinated separately".
Gary Christie, head of policy, communications and communities at the Scottish Refugee Council, said: “The UN Refugee Convention is very clear – refugees cannot be penalised for entering the country illegally to claim asylum. Johnson’s plans are simply unnecessary. If the UK Government truly wanted to stop people making perilous journeys, they would create more safe routes for people seeking sanctuary to reach the UK.
"But Priti Patel’s Nationality & Borders Bill, the anti-refugee bill, doesn’t include plans for any such routes. We urgently need this government to take action to prevent tragedies in the Channel and commit to resettling 10,000 people from across the world in the UK each year.”
However, Enver Solomon, chief executive of the Refugee Council, described the plans as "cruel and inhumane".
"It's a desperate move by a government that isn't able to find solutions that will ensure an orderly, manageable and fair asylum system," he added.
The Navy was last brought in to patrol the Channel three years ago.