Home Secretary Shabana Mahmood said deportation flights into mainland Europe were “under way and ramping up”, warning migrants trying to cross into the UK by small boat to “think twice before making that journey”.
The 19 returns took place on two flights this week, including one earlier on Thursday, and followed seven deportations in the last month.
These were the first group removals under the UK-France pilot scheme, and it is understood more flights are scheduled for take-off over the coming days and weeks.
Nine eligible migrants have entered the UK this week as part of the exchange deal, and they were subject to rigorous security checks, according to the Home Office.
Ms Mahmood said: “We must put an end to these dangerous crossings which put lives at risk and money in the pockets of criminal gangs.
“The contrast couldn’t be clearer. The last government’s Rwanda scheme took years and cost hundreds of millions of pounds, and failed to forcefully remove a single person.
“In a matter of weeks, we’ve returned 26 through our historic agreement with France.
“With flights to France now under way and ramping up, we are sending out a clear message: if you come here illegally, you face being detained and removed, so think twice before making that journey.”
These recent departures have taken the total number of deportations under the deal to 26.
In return, the UK has welcomed in 18 arrivals.
Migrants have continued to attempt English Channel crossings into this week.
Late on Thursday afternoon, more than 100 people were seen gathered on Gravelines beach in northern France, waiting for a small boat.
More than 50 migrants were pictured rushing to board a black dinghy which came close to the shore at around 5.45pm local time.
Only some of the people vying to board were wearing life vests.
The group, comprising mostly men and some women, headed out into the English Channel towards Dover.
