On: Sydney tunnel water screen stop sign for oversized...

[to3m]

More severe low-tech solution: https://maps.google.co.uk/maps?q=blackwall+tunnel&hl=en&...

(Blackwall Tunnel, northbound, London)

And again, just in case you missed the scraping sounds the first time: https://maps.google.co.uk/maps?q=blackwall+tunnel&hl=en&...

(For some reason they don't appear to have anything similar going south...)

[tomarr → to3m]

There is a diversionary slip road for overheights (OHT) on the approach to Blackwall after the first pic and before the second. If you've made it to the second (having ignored a good few red lights), expect to be prosecuted.