Walk or cycle from Lands End to John O'Groats
the answer is easy: I do not have the stamina.
There have been great books about this long walk. John Hillaby's Journey Through Britain, which I bought soon after it was published in 1968, was one I read and reread. Even then Hillaby was warning about the steady encroachment of the urban and industrial onto the rural; things can hardly have improved since. Britain nonetheless has plenty of wonderful open spaces and I can only regret that advancing years and some difficulties with my feet rule me out of such a trip.
Even if I were fully fit, I think it would remain a pipe-dream [Do we still have pipe dreams. Should that read vape-dream? Ed]. Much of the trip is unrelenting slog. At the end you can wearily tick it off your bucket list, sure, but all you have really done is walked (or cycled) quite a lot. I walk and cycle a bit anyway. Coming home knackered after 8 miles traipsing through the local woods around beautiful Ruislip is a sufficient achievement.
I have to admit that this is one bucket list item I would have been proud to have done in the past but right now it is one to be binned.