The United Kingdom has begun detaining migrants who cross the English Channel in small boats under a newly implemented 'one in, one out' returns agreement with France. This treaty, which came into effect on August 5, 2025, allows the UK to return some migrants to France for deportation. British Interior Minister Yvette Cooper confirmed the detention of the first migrants under this deal, marking the initial enforcement of the agreement. Migrants detained after arriving in Dover have been informed of their impending removal to France. The policy aims to regulate the flow of undocumented migrants crossing the Channel and is being closely observed to evaluate its deterrent effect compared to previous measures such as the Rwanda deal. The UK government expects to send some of the detained migrants back to France within weeks. The treaty represents a bilateral effort to manage migration across the Channel, with limited returns occurring in a one-for-one manner.