It was in Karting, not go cart leisure carting, but 115 mph 250 cc karting.
@The Blobster has seen press evidence of it.
Got into karting quite late, it was when I worked for the Toyota World Rally Team doing the Middle East Rally Championships, they had some great circuits and karts in Dubai and Aberdabei, and the bug bit.
Must have been a year or two when i returned, I joined the Haverfordwest kart club,which was situated on part of Haverfordwest airfield which had an indoor circuit, in a old WW2 aircraft hanger. it was in there that we broke the 24hr indoor endurance record.
Then questions started being asked about the outdoor 250cc record, we contacted Guinness once again for circuit dimensions, as we were looking to use a disused runway. it was to be 1 mile with 5 chicanes with exits not more than 45 degrees. these took a bit of setting up as they had to conform with the Guinness adjudicators who were present on both attempts. we beat the record by 37 miles, think it was estimated we did the equivalent of driving from Swansea to London and returning three and a half times in a day.
If you'd like to have a look at my world, Google ' 250 cc karting IOM' .