I clearly vastly underestimated the sheer incompetence of the local work force.
Got caught in a jam where there normally isn't one. When I could finally see what was going on, there was one of those mini diggers lying in the road. The workmen responsible were standing around like a bunch of slack jaw yokels in high vis jackets (because they're very healthy and safety conscious having just dropped a digger in the road), looking bemused whilst all drivers cursed them in every known tongue.
Couldn't tell if it had simply fallen off or they'd tried to unload it and made a Top Ground Gear Force style hash of it. Either way, with them parked and it lying down they were blocking almost the entire width of the road. There was just enough space to leave one set of tyres on the tarmac whilst you drove almost completely on a pavement (up a high curb) to get passed.
So well done those workmen.
Tomorrow I now fully expect to drive to work and have my progress halted by a crashed satellite or some such.