More than 3,300 migrants have crossed the Channel so far this month, heaping fresh pressure on Rishi Sunak over his promise to stop the boats.
The desperate asylum seekers are taking longer routes to the UK to avoid the heavily policed areas near Calais and Dunkirk.
A boat carrying 24 migrants was rescued off the coast of Quend on Thursday morning, 54 miles south of Calais.
It comes as people smugglers exploited the improving weather conditions to launch unsafe dinghies into the Channel bound for Britain.
So far in June, 3,308 migrants have arrived on 68 boats, bringing the total this year to 10,962.
This is down just seven percent from last year's 11,806, prompting fresh fears Prime Minister Rishi Sunak may have claimed success too early.
He said the Government's policies on illegal migration had led to a 20 percent reduction in crossings. But the gap between this year and last year's total has been narrowing rapidly over the past week.
Worryingly for ministers, the number of crossings this June has already exceeded the total from last year.
Some 312 people were detected making the crossing on Thursday, the Home Office said.
The French coastguard rescued another migrants off the coast of Quend beach near Berck, northern France in the early hours of Thursday (June 22) morning.
Quend is 54 miles south of Calais, prompting further concerns smugglers are spreading out along the French coast. The migrants were taken to Boulogne.
The busiest day came on June 11 when 549 migrants arrived in Dover in 10 vessels.
Comparatively, by June 22 in 2022, 11,806 asylum seekers had made the crossing.
Last year, a record 45,755 people crossed the Channel in inflatable dinghies or other small craft - 60 per cent higher than the previous year which saw 28,526 migrant crossings.