“More than half of net migration to the UK comes from the EU. More than a quarter of a million people came to the UK from the EU in the 12 months to September 2015 - the equivalent of a city the size of Plymouth or Newcastle in just one year”
The first part is wrong. Net migration of citizens from the rest of the EU was 172,000 in that period. Net migration from the rest of the world was 191,000. So the EU doesn’t make up more than half of net migration.
Overall net migration was 323,000, because at the same time 40,000 more British citizens left than came in.
The second part is correct. Over a quarter of a million immigrants came from the rest of the EU according to official estimates. That’s around the same as Plymouth’s population but not quite as much as Newcastle’s.