Purpose of Vent Protruding from Ground

Hi,

I'm about to re-lay a concrete path and have a vent protruding that I'd either like to remove or tidy up.

Haven't been able to figure out where it goes or how deep it is.


Would anyone know what it's for, if it's safe to block it and concrete over it and if not if there is anything I can replace the current outlet with that looks neater and is less of a trip hazard?

Thanks

Darren

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