And for those who have never had to fix a puncture on the side of the road, here is how I did it (note: not intended for those who have done this often, but this really is Puncture Repair 101):
I carry a German-made puncture repair kit, and these are the component parts:
It's probably all self-explanatory, but anyway, from left to right:
1 - T-tool for reaming out the hole and inserting the plug
2 - chalk for marking the site of the puncture
3 - rubber cement
4 - knife tool for trimming the plug when inserted and before riding
5 - adapter for screwing into CO2 bulbs and tyre valve stem
6 - top right: pack of 3 (1 used) 'figure 8' style plugs
7 - NOT SHOWN - 3 CO2 bulbs (cylinders that came with the kit)
When I stopped the tyre was already completely flat, and the screw/nail whatever had been thrown from the tyre. I speculated it was a screw, as the hole was neatly reamed:
After reaming the hole a little more, I coated the T-tool with rubber cement, and inserted this in the hole, getting as much cement in/around the hole as possible. I fitted a plug into the shaped eye at the pointy end of the T-tool, coated it with cement, and inserted this into the hole. It feels far too big, and as if it won't go, but the plug stretches and suddenly pops into place. Immediately remove the tool. The shaping of the 'eye' leaves the plug in place as the tool is extracted.
Leave to cure for about 5 minutes, then inflate with CO2 bulbs. Make sure you are wearing gloves when holding the bulb, as the relaese of CO2 causes the bulb to cool immediately and significantly - you can freeze your fingers to a bulb if not careful. The three bulbs that came with the repair kit only took the tyre to 15psi, so I now carry a small compressor that plugs into a lighter socket I have mounted under my seat.
About 4,000 k's after this repair the tyre developed a slow leak (10PSI over 2 hours riding). As it was only 1,000k's to replacement, I just 'pumped and go', but when the tyre was removed I found another puncture caused by a small nail about the thickness of a thumbtack. The external hole was so small that 5 or 6 detailed inspections had missed it. After 5,000k's of fairly aggressive riding the plug was still fine. I did not do much high speed riding in this time, but lots of twisties.
And, for info, this is what the plug looks like inside the tyre after 5,000k's of riding:
And close up: