http://townhall.com/columnists/CalThomas/2007/08/28/vanishing_england
That is the Cal Thomas article which states that between 2005 and 2006, 200,000 Brits (presumably native) left Britain while nearly three times that number gained entry to Britain from presumably non-EU countries.
I am not surprised by PM Brown’s actions, though I suspect it neither gets at the real problem. The real problem is on display in a photo one or two posts above this one. (The protestor with the sign seems very fluent in English already.)
Around 50% + of UK citizens who have emigrated over the past decade have returned to the UK. It is quite a complex picture.