The right one to take over as leader of the Tories would be Tony Blair, crossing the floor of the house, as a one-nation Conservative. There's nothing in his politiocs that would have upset Macmillan or Macleod, though he might have been a bit right-wing for their tastes on a few issues.

Tories have always prided themselves on being pragmatic and adaptable to achieve power; and as the leader of a reformed New Conservative Party Tony would probably have a much longer shelf-life as a successful politician, and he'd be in the History books for something other than Iraq.