Its Victorian era, and they sunk ventillation shafts from unused land on the surface and then connected them below ground nowhere near in a straight line
More than a mile away from the tunnel but the lane on the left is the queue. On a Sunday its easier to drive past and do a 360° on the next roundabout come back from that side
The southbound Blackwall tunnel is only 50 years old and much straighter. Although we'd have had a massively needed bridge in East London by now if Boris hadn't been elected