Farthest distance travelled on a unicycle in 24 hours

According to Official Guinness Records,

Sam Wakeling (United Kingdom) covered 453.6 km (281.85 miles) on a unicycle in a 24 hour period at Aberystwyth, Wales, United Kingdom, from 29 to 30 September 2007.
Sam used the event to raise over £1500 for Christian Aid.

For a complete list of 2007 records, please visit 2007 Guinness Records in United Kingdom.

Other United Kingdom records that might interest you:

• Longest continuous unicycle ride
• Largest pedal-powered vehicle
• Karting - greatest distance in 24 hrs outdoors (team)
• Fastest speed on hydro-jet powered kayak
• Most faces painted in an hour (individual)