Nearly 2,000 migrants arrived in the UK in the last week, setting a new record for the year so far.
A total of 1,959 people crossed the Channel from France in the week to September 10 – the highest total for any seven-day period in 2021, data compiled and analysed by the PA news agency shows.
It comes as more crossings were under way on Monday amid reports of cooler and slightly overcast weather on the south coast with breezy but clear conditions at sea.
Several young children were among a group seen arriving in Dungeness, Kent, while immigration officers were pictured tending to a woman who had been taken ill after she was brought ashore on a stretcher by police and members of the RNLI.
At least 14,400 people have crossed to the UK on board small boats this year.
Figures for the most recent seven-day period, covering the week to September 12, show that 1,876 people arrived.
The total for 2021 so far is already just over 6,000 higher than the number of people who made the crossing in 2020.
Last week Britain and France became embroiled in a war of words over efforts to halt the crossings, with French interior minister Gerald Darmanin hitting back at Home Secretary Priti Patel after it emerged she had sanctioned tactics to turn back migrant boats towards the continent to stop them making the journey to the UK.
Mr Darmanin said France would not accept any practices which breach maritime laws, or be subjected to financial blackmail – a reference to suggestions from Ms Patel that she could withhold millions of pounds of cash promised to help step up patrols unless an improvement in the number of migrants intercepted by French authorities is seen.
The suggestion that so-called turnback tactics would be used has prompted an outcry from aid charities and campaigners who fear the plan could risk the lives of migrants, with some experts warning it could be dangerous.
The legality of the tactic was also called into question, even though ministers have insisted the UK would not infringe international law in seeking to tackle the crossings.
Border Force staff are understood to have been given special training on handling migrant boats, with the decision on how to approach an incident down to individual captains.
The tactic could reportedly involve officers on high-powered, armoured jet skis being used to physically turn dinghies around before escorting the boats back to France.
The complicated manoeuvre requires two jet skis to circle the boat, with one pushing it back from the bow and the other nudging the stern at its motor, according to The Sun.
Border Force appeared to be carrying out exercises on Monday afternoon off the coast of Dover which – according to reports from eye witnesses – involved jet skis manoeuvring around a dinghy while other larger vessels were stationed nearby.
The Home Office said it does not routinely comment on maritime operational activity relating to border security.
But a department spokeswoman said: “As part of our ongoing operational response, we continue to evaluate and test a range of safe and legal options for stopping small boats.
“All operational procedures used at sea comply and are delivered in accordance with domestic and international law.”
The Home Office would “continue to explore all options available” to reduce the number of crossings, the spokeswoman added.