The ONS has provided a preview of the 2011 census. They have released some bare-bones immigration numbers. The UK population has gone up by four million people in the last decade. This is mainly due to two factors: immigration, and immigrants having children.
Of course we already knew the country has been swamped by immigrants. We can tell just by walking down the street. The ONS seems to be softening us up slowly though. They have not yet released the ethnicity or religion numbers.
As a reminder this is how the country stood in 2001:
It will be very interesting to see how the numbers have changed in the last ten years. I have a feeling certain religious groups will have grown massively. (Once we have two data points we can start making projections.)