Oh bugger! Set off at 3.25pm to do a 50k and got my first flat since about 3000 miles back. Six miles from home on the outward journey. Spare tube out and fixed it.
Got another half mile and the new tube flatted. I'd checked inside the tyre before fitting the tube as I couldn't see anything obvious from the outside and it was fine.
Mystified, I had a long-ish trudge home. Took just over 2 hours and included shoving my bike up two steep-ish hills - deep joy!
Got home and took the tyre off and still couldn't find anything. Turned it inside out and slowly worked my way around it and I just spotted the tip of a tiny thorn that appeared as the tyre flexed.
Must've been working it's way through the thick protection strip (Marathon Deluxe) for some time - was an absolute mare to dig/pull out as well.
Can I please have 50 points for effort and a heroic walk back home?