Depends if Scotland votes for the Scot again it could be Murray.
That's the problem with SPOTY. Too many people vote for political reasons, not on merit. Cycling fans will vote for a cyclist, the horsey crowd for one of theirs etc.
Remember the controversy on here last year over CW's campaign to back Chris Hoy above people like Nicole Cooke, for example. When Simpson won it in 1965 it was after The Comic's campaign had resulted in a huge cyclist's vote for him. They have done nothing people in other sports don't do every year, but that just shows up the true merits of the award.