You tow them back, leave them on the beach where they started out from, no need to even tell the French who would also get their life jackets back.
Or, you Trump them then dump them, back in their own countries or, we develop one of our uninhabited islands and create a holding facility like the Aussies did, it stopped the boats pretty quickly. We spent all that money on Rwanda, lefties blocked it at every turn then scrapped it and the Germans moved in and said thank you very much and adopted the infrastructure we'd paid for.
We have to stop making the UK such an attractive option, it's absolutely, unsustainable and has been for several years, we waste so much money that could be used at home.