Can you ID this?

[Steve T]

I am very rarely stumped by a relic from WW2, but this one is driving me nuts. Recovered from a British army dump site that is full of weapon and tripod parts, this is one of 10 of these items I've now recovered over the past couple of years, but I still cannot ID it!

 

Any thoughts or ideas, please let me know!

 

[Steve T]

Come on guys! Don't let me down! Someone must recognise this damn thing. Roughly 6 inches from tip to tip, screw thread, cam fastener that swings up and down........

[Guest Fred Karno's Army]

It has me stumped this 

[Steve T]

Me too......driving me NUTS! Only relic from hundreds from this site that I haven't yet ID'd.......