|credit: Shane Pope|
Fairly at the beginning of this interview Al-Khalili asks Richard Dawkins: "With these two books do you think you hit a nerve or need among the general population?" To which Richard Dawkins replies: "Two different nerves I suppose. I mean The Selfish Gene is about biology, is about evolutionary biology and although at time I thought I was just laying out what was a kind of orthodoxy and it turns out that perhaps that wasn't quite right."
What is interesting here and what Jack refers to in his blog is the way Dawkins pronounces the word highlighted in my transcript - "perhaps".
Listen to the section "[...] and it turns out that perhaps that wasn't quite right."
There's no /r/-sound audible.
The 'big three' do not mention this informal variant pronunciation, although they do record /præps/. You needn't imitate the r-less variant, but should be prepared to stumble across it.