Watch her closely and—or so the upper echelons of British espionage felt—you could see the signs. There was the cut of her hair, for one thing: that close, spiked crop. Something, too, in the way she held herself. And she was a woman. There was, everyone agreed, little doubt. Dame Judi Dench’s “M” in the 1995 film “GoldenEye” was based on Dame Stella Rimington, the first female head of MI5, Britain’s domestic counter-intelligence and security agency. Dame Stella agreed: she “holds her hands in the same way as me”.