>he faces the threat of extradition and execution if he answers the call to be questioned on Swedish soil.

A threat that he, and only he, has elucidated. There's no extradition request in place, and Sweden isn't actually a banana republic whereby the government can order the courts to approve an extradition request.

>Third, the UK has spent millions each year to make sure he doesn't get away.

Well, yes. He's a wanted man. You generally don't want to let those slip.