No victory (Beware - contains spoilers)
After watching Smiley's People I was struck by the thought that Smiley does not consider Karla's defection a victory. His demeanour throughout the walk-over implies both disappointment and disinterest, as he does not want to look at the event and is unexcited, unlike the jovial Toby ...
I think this is because Smiley doesn't like exactly how they brought about Karla defection. They've coerced him into coming over, rather than respond to his request for extraction. He would most probably maintain his Soviet allegiance whilst in England or at least belief in Soviet ideology, think of the flat refusal to defect Karla gives Smiley in Tinker, Tailor ... On this basis, the information he gave the British would not be able to be fully trusted.
I think Smiley would have been happier if he decided to come of his own volition rather than blackmail over his daughter, who is only a pawn in their game.
What do the rest of you think?