Until the early 1990s, the number of people leaving the UK exceeded the number of people entering.
Currently, about 1500 people every day enter the UK to live here; every day, about 1000 people leave.  This is the highest rate of out-migration since records began.  About half of the out-migrants are British citizens.
A quarter of the migrants are from the EEA25 area, who must be working or be able to show financial independence.
As a proportion of population, the UK ranks 14th in European countries for asylum applications, about average.  France gets the most by number, Cyprus, Malta, Austria and Sweden the most by proportion.
Migration accounts for 66% of the increase in population in the UK.

Data from Social Trends, from 2005.