Walking to faster running times

Sounds counter intuitive doesn't it? If I walk more then my times will be faster?

It puzzled me that my third run of the holiday was so much slower (almost half a minute on a 24 minute run) than my second.

There could be a number of rational explanations for this - different weather, more fatigue etc. etc. But the other difference in the runs was that in my second run, I walked about 25% of the way back to my starting point, whereas in the third run, I decided I was going to run the whole distance.

On my second run, I used the telegraph poles to ration my walking - so I guess it turned into a bit of an interval or fartlek session. I walked to one pole, jogged to the next one, and then ran through the next two before walking again.

I'm not yet convinced that run-walk is necessarily quicker for me (you certainly don't see many people doing it at the Wimbledon Common Time Trial), but this article from Jeff Galloway on Run-Walk seems to suggest it would be quicker by delaying fatigue. It may even be a way of reducing soreness or injury after the run.

So I've got a choice to make today - run-walk, or just run?

Anyone else had experiences of this? What do you think is quicker?