Rishi Sunak said he wants people to “have confidence” in his plan to curb Channel crossings, as the total so far this year approaches 20,000.
The Prime Minister said the number of migrant arrivals was lower than last year and this showed his plan to “stop the boats” was “working”.
Crossings resumed on Tuesday, with pictures showing a dinghy packed with men and boys, some without lifejackets, perched on the sides while their legs dangled in the water.
According to witnesses, a nearby French patrol vessel appeared to be escorting and monitoring the boat as it floated into UK waters towards Dover before it was met by Border Force and later taken ashore at the Kent port.
Provisional Home Office data shows that in 2023 so far 19,801 migrants have arrived in the UK after crossing the Channel.
This is 21% down on this time last year when more than 25,000 people had already made the journey, PA news agency analysis of Government figures shows.
The pace and volume of crossings slowed over the bank holiday weekend, with just 60 people detected making the journey in one boat on Sunday and no crossings recorded on Saturday or Monday, according to revised Home Office figures.
Speaking to broadcasters on Tuesday during a visit to Norfolk, Mr Sunak said: “This year, for the first time since the small boats crisis emerged, the numbers crossing are down. It’s important for people to understand that.
“This year for the first time the numbers of people crossing are lower than the year before. That hasn’t happened before. That shows that the plan is working.
“Of course, there’s more to do, but I want people to have confidence that we are on it, and we’ll keep going.”
Mr Sunak previously played down suggestions that the lower number of crossings compared with last year was linked to poor weather conditions rather than policy decisions.
But this summer has seen more unsettled weather compared with last year when there was a spike in crossings in August.
While June 2023 was the warmest on record, July and August have been much more unsettled, with a sequence of low pressure bringing wind and rain.
Summer 2022 was the fourth warmest on record for the UK and the warmest on record for England, with heatwaves in each of the three months.
When questioned, Mr Sunak was also unable to say when migrants would be moved back onto the Bibby Stockholm barge in Portland, Dorset.
“We’re working through making sure that all the regulations are followed”, he said.
The first asylum seekers arrived on the barge earlier this month but were moved off again just days later after tests revealed Legionella – the bacteria which can cause the potentially fatal Legionnaires’ disease – was present.
Home Secretary Suella Braverman has insisted the giant vessel is safe amid threats of legal action from firefighters.
In other developments, Kent Council said it had been “forced” into failing to meet its duties to care for lone child migrants as it branded the National Transfer Scheme (NTS), which is meant to spread the responsibility between local authorities around the country, “wholly inadequate”.