Most copies of this classic UK only pressed single contain a speeded-up section in the middle of the B-side for about 30 seconds. However a few copies were also available without this fault, but are much harder to come across. Usually attributed as a pressing fault, due to the pitch staying the same, this is unlikely to be the cause. One theory is that an engineer had a little fun with an Eventide Harmonizer that was just around in big studios at the time, which had the effect of keeping constant pitch whilst speed changes could be done. This to me seems unlikely as this wouldn't have been done on a commercial release with the various pressures this puts on engineers to do a good job. So perhaps the mystery continues...

I think this is commonly called "time-stretching" these days, now that all and sundry can get a similar effect by software, too:)