1926 dieclash spur
1926 dieclash

This is a 1926 Penny that shows a die-clash where the facial side of the obverse is clearly shown as indicated by the red arrows. What appears to be  markings at the back of the head don't seem to line up.

1926 dieclash spur_1
1926 Outlines

In this image I have highlighted the rough outline of the facial features to make them stand out more easily. The outline clearly shows the facial features from the obverse side in reverse.

overlaid 1926
1926 Overlaid

I have overlaid and lightened the reverse side onto the obverse as a die-clash would occur and the facial areas line up extremely well, making me consider that my hunch is correct.

neck detail
1926 Neck detail

I have highlighted the area at the chin and neck. I put several of these "spurs" on the coin forums quite a few years ago and the consensus was they are spurs. I disagree and believe they are actually caused by die-clash. If you look at the shape of the highlighted area, it closely mimics the shape of these "spurs".

1924 Penny dieclash 2
1924 dieclash

This 1924 example show the "spur" on the second N in PENNY, where they all seem to occur, but also shows the outline of the facial features. This is a die-clash in my opinion. Some of the "spurs" show on the N but no facial features are apparent, and there are some multiples following.

1924 Penny dieclash 1
1924 Overall

Another view of the same coin which shows the back of the head clearly and also the ear. There are several more images to follow.

triple spur 4
1919 example

This is a 1919 example of what is generally considered as "spurs". There is a  close-up view of the same coin in the next image.

triple spur
1919 triple

A triple "spur" which could only occur with multiple die-clashes and die rotation during the time the die was used to strike the number of coins required. The third "spur" is less easy to see and is the lowest. I have a few George V coins showing some amount of rotation.

100_2908
1921 single

Close-up image of a 1921 example. I have doubles as well but you get my drift on these.