The thorn Alpha 1 is a rare lantern now. It was one of the first lanterns to have a sealed optic system, and they normally have a 90w SOX lamp.

Royal Mail depot, Richmond

These thorn Alpha 1s are in the Royal Mail depot in Richmond. One of them is Dayburning. I took this photo through the fence.

Here is a non-Dayburning alpha 1 in the same place.