Migrants who cross the Channel in small boats should be returned to France before they can apply for asylum, the former head of the Border Force said.
Tony Smith said it would be the only way to stop people smugglers risking the lives of vulnerable people.
An agreement between French and British governments would be needed, he said.
Home Office minister Chris Philp said the government was “reviewing laws that prevent us from taking stronger action to stop illegal migration”.
Priti Patel and her French counterpart Christophe Castaner pledged in September 2019 to make crossings an “infrequent phenomenon” by spring 2020.
More than 2,400 people have crossed the Channel in small boats this year, while at least 4,500 have done so since November 2018.
Mr Smith, who served as Border Force’s interim director general between 2012 and 2013, told the BBC that returning migrants to France would “send a message to the smugglers that it’s not going to work”.
‘People will drown’
Turning overcrowded boats back at sea is “really quite difficult” without risking lives because migrants have been “coached” by smugglers to resist rescue by the French and only accept assistance from British vessels, he said.
Britain currently has “no authority to return them to France”, so once intercepted by Border Force migrants are brought to the UK, where they typically claim asylum, he said.
“The only practical solution that I think can be achieved would be an international agreement with the French that would enable us to return people, once we have established they are safe and well,” he said.
He said all efforts so far on both sides of the Channel had failed to “break the mould,” adding: “We have got to find a way of stopping this because people are going to drown.”
Bridget Chapman, of Kent Refugee Action Network, said the government should instead offer “safe and legal passage to those looking for refuge”.
“Shutting the door in people’s faces will not solve the problem and it is an abdication of our moral duty,” she said.
French Conservative MP Pierre-Henri Dumont has previously called for migrants to be allowed to claim asylum at British embassies across Europe.
Mr Philp said the government was “tackling these crossings at every level,” adding: “We continue to work tirelessly with our French counterparts who have stopped over 1,000 migrants this year from making the perilous journey.”