Berwyn played for Wakefield in the 60s dont think he played too long I thought he was a sprinter and didnt Leigh have an Olympic spriner who only played the one game in which he scored?.
I would guess that Berwyn Jones was the fastest man to play first team Rugby League, and without doubt the fastest player to represent Great Britain at Rugby League. Radford, Jones (Berwyn), Jones (Ron) and Jones (David) beat a crack US squad at the White City in the 4 x 110 yds relay in a World Record time, and Berwyn was the British 100 metre record holder when he joined Wakefield Trinity. There were, of course, a lot of so called professional sprinters around at the time, who competed in events like the Powderhall Sprint, but the top amateurs were the real flyers.
Two other possible contenders, Alf Meakin of the same era, was, I think, an Olympian, and played RL for a while with Backpool. Now I'm less sure of this next suggestion, but I think that David Jones, who still holds the World Record at the obscure distance of 150 yard, tried his hand at Rugby League in Australia (but I am relying on a very dodgy old memory, so don't take it as Gospel).
The Leigh sprinter, I'm guessing, was MacDonald Bailey.
If we include second team games, then Chamberlain must be the quickest ever to play a game of RL.