Cyclists are more at risk through road works and TFL have specific guidance on this (my bolds):
"Where cyclists are on-carriageway and the speed limit is 30mph or 20mph, it is usually desirable to keep them on carriageway through the roadworks. In this case, a wide lane (minimum width of 4m) enables drivers of all motor vehicles to overtake cyclists with an acceptable clearance.
If a 4m lane width cannot be achieved then, according to advice given in TAL 15/99 Cyclists at Roadworks (1999), a ‘narrow’ lane width of up to 3.25m to 3.50m will enable car drivers to overtake comfortably and will generally deter drivers of larger vehicles from trying to pass at all.
If 3.25m cannot be provided, then a ‘narrow’ lane width of up to 3.25m and a speed limit of 20mph should be considered with signs stating ‘narrow lane(s): do not overtake cyclists’. Lane widths between 3.50m and 4m should normally be avoided as drivers of large vehicles may attempt to overtake cyclists without adequate clearance."
The lane widths in the clip are not easy to estimate - but look around the 3.5m (using the 2.5m wide bus as a guide)...Hopefully, the investigation into this tragedy will examine the lane widths and best practice guidance.
I've just come back from a car journey that involved driving through some roadworks near a level crossing that involve closing one lane, seemingly to enable work on the footway. (Spring Bank West heading to Princes Ave for locals)
There are signs saying "cyclists dismount and follow pedestrian route" helpfully followed by "footpath closed". (I think it's actually a 'footway').
The roadworks are about 100m long, on a stretch where traffic moves slowly at the best of times, as other traffic is usually trying to join from the intersection, and both should be anticipating the crossing barriers coming down as it's a busy stretch of track.
If I was on my bike, I would ignore the information boards, take primary, and no doubt suffer the abuse from drivers. What looks like the pedestrian route, involves crossing the dual carriageway twice and a side road, which in my opinion adds a lot more risk factors, and is unnecessary.
It's on for 4 months, so I reckon a call to highways is in order.