Well I don't see it that way, Major came to power in recession which fits with people voting based on how they feel economically. Labour remained in power until (yet again) economically things took a nosedive and then they were gone again.
Ok, but if you remember the times when there was a gulf between left and right (nationalisation vs privatisation as one example) how was it that the floating voters jumped that gulf? Could their thinking really change so dramatically in so short a time?
The explanation is that they wanted the government out and jumped to vote for the party most likely to achieve that result.