This is my attempt to rank the notable long runs I have completed according to difficulty. Doubtless some would disagree with the placings! This list could be used to identify intermediate steps in building up to a challenge. They are not all ultras, the “short” ones start from around 30km+. Some general observations:

• Races are often harder than anytime challenges (assuming you have pacers on your challenge!) because of the kit carrying requirements. A solo unsupported effort on a challenge is likely to be the daddy in terms of difficulty.
• Race/challenge cut-off times or limits have been taken into account – some (e.g. Lakeland 100 having a 40-hour limit) are quite generous, which has affected the ranking on here. Obviously if you bust a gut to get the best possible time, it will feel harder!
• Terrain is also relevant – sometimes this is a major limiting factor, e.g. on Tranter’s Round.

I have included hyperlinks where possible to either official race/challenge websites, or my own strava log. Also, please do take a look at the excellent list of challenges at gofar.org.uk for inspiration and a really thorough list. Those marked with an asterisk also appear as separate posts in my blog.