I haven't been able to confirm that's what happened, but it looks very likely.
Now confirmed - it collapsed on Thursday, there were no casualties.
I also took a picture of a light rail system serving the tunnels; the rails have been in place for ages, but it's the first time I've noticed a vehicle using them:
Finally, here's another family of swans on the canal; this time the young are a little smaller that the adults
Ahead of mum and the kids