Updates via Alan Young at trackside and from the Swedish website http://www.jogg.se/liveresultat (Thanks to Torill Fonn for the link).

Alan tells me that at 4hrs William had covered 37.2km (about 23 miles). Alan tells me that the weather is good with a temperature of 22c and that it is sunny and a little windy.

Details of all runners with current positions and distances are shown in the screenshot below (click to enlarge).