...with apologies to those who dislike my multiple postings, I have not answered Jono's question about students.
Students are not counted among the "net" immigration figures, because they do not settle here permanently (not legally, at least). They are here for the duration of their study and then they are required to leave because their visa only allows them to remain for study. If they subsequently wish to remain, they have to apply again for a new visa that permits them to work here, and then they will appear on the new migrant statistics as coming here to work rather than to study.
The GROSS number of migrants coming here annually is almost 600,000, including around 230,000 students. According to the quarterly migration report from the ONS:
"Emigration reached its lowest calendar year figure since 2001 at 339,000 in 2010. Immigration remained steady at 591,000."
"The estimated number of non-British citizens immigrating long-term to the UK in the year to March 2011 was 458,000"
"The estimated number of long-term migrants whose main reason for entering the UK was formal study was 229,000 in the year to March 2011"
"The total number of entry clearance visas for work and study issued in the year ending September 2011 was 494,600"
So, the number of entry visas issued, excluding the 229,000 students, was around 265,600.
So, students coming here are a good thing for the economy, providing they are really students and they do not remain here at the end of their study.
The net migration figures that relate to the increase in the permanent population due to permanently settling immigrants DO NOT include the number of students in the gross migration figures.