Looks like Iw/T: INERT WITH TRACER: standard training ammo.
On the other hand, it could also be AP with Trace.
I doubt that it would contain any filling: nowhere for it to be filled into, also no fuse assembly. If you find another with a big brass fuse assembly on the front end.... keep clear.
This look about the right shape to be for an 18-pdr but there were a lot of guns about that size. Try weighing it; weights were controlled carefully.
If you clean up the base of the thing with some steel-wool, there could be something stamped there. Also, on a lot of arty ammo, there were factory markings on the SIDE of the projo, about halfway up. These generally give a factory designation, what size it is and a date when it was made.
It is a very interesting artifact.
Clean it up, check it out, learn about it, display it.
And have fun.
That's what it's all about.
BTW, the cops never 'make it safe'. They take it away from you just to protect the public from being frightened and then it ends up in one of their collections. IF it contains explosive, then the Army lays a slab of C-4 up against it and sets it off. But nobody 'makes it safe'. In this case, I think it was 'safe' right from the day it was made...... but don't drop it on your toes! It is VERY hard material, whatever it is: notice the bit CHIPPED out of the point; makes me think it is what they used to call 'shot', a solid hardened projectile used as anti-armour until armour got too thick. Tracer element generally screwed into the base.
Hope this helps.
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