We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Dave Liquorice"
saying something like:

After all they installed a girder bridge when the Eden washed away
the sandstone bridge at Langwathby in 1968. That Bailey type bridge
is still there and is probably the oldest "temporary" bridge in the
country.

I've seen a few Bailey bridges dotted around the UK, and I distinctly
recall the first one I encountered in 1962ish was on a road just south
of Ayr. It was still there a few years ago, surprising me somewhat as I
had expected it to be gone by then.