I don't know anything about it other than it has been in the same ownership since sometime in the 1960's/70s when it was purchased from a wood and timber auction along with the smaller Costain sign which I also have listed here.

Is it ex military? I honestly don't know for certain but would assume so.

I have not washed it, just brushed the dust off with a soft brush. Cleaned up with a bit of polish applied it would make a great statement piece.

The back has never been painted as shown in the picture.

It is very genuine and very heavy.

Collection only from SN14, approx 3 miles from Junction 18 M4.

Any questions, please ask.

Thank you for looking.