Mats Persson is an EU migrant on whom David Cameron’s future depends.
The 36-year-old from small-town Sweden has been propelled into Downing Street in the hope that he will play a key role delivering the impossible — a meaningful renegotiation of Britain’s relationship with Europe.
Until he disappeared to become a special adviser in No 10 almost a month ago, this 6ft 7in blond was an unmissable figure in the Westminster village, dominating the EU debate on TV, social media and across the political scene.
As the director of Open Europe, he steered this high-profile European think tank away from the insurgent, aggressive campaigning roots which go back to the efforts to stop Britain joining the euro.
Instead, under Mr Persson’s tenure, it became an