I think you should review the Highway Code.
There is a general responsibility ("should" - it's guidance, not the law) on all vehicles to "only overtake on the left if the vehicle in front is signalling to turn right, and there is room to do so" (rule 163) and some advice for all road users on all "
Large vehicles. These may need extra road space to turn or to deal with a hazard that you are not able to see. If you are following a large vehicle, such as a bus or articulated lorry, be aware that the driver may not be able to see you in the mirrors. Be prepared to stop and wait if it needs room or time to turn.". But that's only advice - rule 221
But there's an over-riding requirement on all drivers ("must" - it's the law): "You
MUST exercise proper control of your vehicle at all times." (Rules 149 and 150. It's so important that it's stated twice). And in rules 151 to 153 the responsibility to look out for cyclists is re-stated, especially in slow-moving traffic: "
In slow-moving traffic. You should [...] be aware of cyclists and motorcyclists who may be passing on either side." and on residential streets and at junctions: " Take extra care at junctions. You should watch out for cyclists, motorcyclists, powered wheelchairs/mobility scooters and pedestrians as they are not always easy to see. " (rule 170)
And from the DVSA's advice specifically for lorry drivers...
"
Turning left
When you’re turning left, [...] You should [...] make sure the area to your left is clear before you start to turn: vulnerable road users such as cyclists might move into this area and are difficult to see." (
https://www.safedrivingforlife.info...l-driver/lgv-knowledge-centre/your-lorry-road)
The legal and moral responsibility for road safety rests primarily with the operator of the most dangerous vehicles. Overwhelmingly, death and injury to vulnerable road users is not the fault of those vulnerable road users. It's the fault of the operators of dangerous vehicles. And there's a special moral responsibility on lorry drivers who are also cyclists to recognise that fact and challenge any assertion to the contrary.