Net migration was unusually high in 2023, and it was overwhelmingly legal migration. Hundreds of thousands of non-EU work visas were issued. Many of them were for workers in the NHS, schools and other public services. There were also hundreds of thousands of study visas for students.
The conservative government chose to have very high net migration last year (685,000) to prop up the NHS and economy. They wanted migration to be that high, it was a choice,
The number of people who came in small boats in 2023 was under 30,000. If the tories had managed to stop every single one then net migration would still have been over 650,000. Talking about small boats is a way of making it sound like you want to reduce migration, when in reality you just don’t want to tell the public that you’ve decided that these levels of migration (that they don’t like) are needed for the economy and the NHS to function.