After googling around a bit, it seems Noitartst is referring to this:
wiki writes:
The concept of c-decay was first proposed by Barry Setterfield in 1981 in an article for the Australian creationist magazine, Ex Nihilo. He selected a number of historical measurements of c starting with the original measurement by Ole Rmer in 1667, and proceeding through a series of more recent experiments, culminating in "modern" measures in the 1960s. These showed a decreasing speed over time, which Setterfield claimed was in fact an exponential decay series that implied an infinite speed in the not distant past.[2] The claim was later expanded to cover an apparent similar decay of several other physical constants.[3]