Help me identify this plz

[AJ10]

I plan to do garden renovation in a couple of weeks' time, I have shared a manhole in my back garden and this mini cover right next to the house, few meters away from the shared manhole (pics attached).

I have no idea what it is for. There is also wet soft sand inside it, does anyone know what it is? Was it meant to have soft sand in it or do I have a bigger problem hidden underneath it?

A bit of digging on google shows it might be stop cock, if so, is there any harm in taking out the sand?

Thanks
AJ

 

[charliegolf]

It looks like your house's water stop cock (clue on the lid!) They often fill with crud carried by rainwater. If you clean it all out with a scoop or spoon, you should find the valve. It may not have a tap top on it- they often need a tool. Its purpose is to isolat the water supply to the whole house.

 

[Dangee]

The clue is cast into the lid!!!!
Stopcock.

 

[EFLImpudence]

Is there not an app for it?