Well, ultimately we all came from the Rift Valley (or so they say). So even without subsequent intercontinental communication there may have been a common ancestral predisposition to build pyramids. I keep an open mind towards such matters and I certainly wouldn't be arrogant enough to declare that Neolithic communication between Egypt and Britain was a total impossibility. However, the evidence is flimsy and circumstantial at best and certainly doesn't warrant the categoric support that some people seem to give it.