Michael Caine – no. Not lovable enough.
Graham Norton – no. Too vulgar, and too stupid at the time of the invasion of Iraq.
The actor, Adrian Lester, in years to come?
Yes to Fergal Sharkey (in about ten years from now).
Yes to Tom Baker.
Yes to the aforementioned Michael Rosen.
Yes to the historian Mary Beard.
Possibly, in about a decade or more, Brian Cox, the scientist, will become a national treasure.
Perhaps the scientist Maggie Aderin-Pocock may become a national treasure, but she is not widely enough known at present.
In twenty or thirty years, perhaps the biblical scholar Francesca Stavrakopoulou will become a national treasure.
Bettany Hughes, the historian, in years to come?
Carlo Rovelli, the scientist (if he moves to Britain)?