A second person taken in France under “one of the government’s, one, one” Deal “has returned to the UK, confirmed the home office.
The unidentified man who arrived in the UK later joined around 400 people who crossed the channel in small boats on Sunday.
The home office said the man, whose age and nationality have not yet been disclosed, was identified by biometrics as one of 94 migrants removed from Britain under the UK-France Treaty in the past two months.
He was immediately arrested and the department said he would be taken to France “as soon as possible”.
The man is the second migrant to return to the UK after being picked up by France following the arrival of an Iranian man on 18 October, as revealed by the Guardian.
He returned in a small boat less than a month later which was one of the first taken by France under the treaty.
Confirming the sighting of the second arrival in the UK, a home office spokesman: “Anyone looking to return to the UK after this has wasted their time and money.
“This individual was detected by biometrics and immediately detained. His case is urgent, and he will be returned to France as soon as possible.
“The message is clear: if you try to come back to the UK you will do it again. We will do whatever it takes to crack down on illegal migrants and secure our borders.”
The Home Office has not yet confirmed the total number of migrants who arrived on Sunday but it is estimated to be around 400.
They followed 1,772 who crossed in 25 boats on Thursday, Friday and Saturday as smugglers took advantage of calmer conditions in the channel.
Under the “one in, one out” approach, British officials intercepted some crossing the channel and sent them back to France. In return for taking each person, the UK takes an asylum seeker in France who can show they have family connections to Britain.
The agreement was announced in July by Keir Starmer and Emmanuel Macron. Speaking at a joint press conference, the prime minister said: “There is no silver lining here, but with a joint effort, new tactics and a new tactics and a new tactics and a new level of intent, we can turn the tables.”