We have guys who install fencing and prior to any digging works, such as creating the holes to lay fence posts, all areas are subject to CAT scanning. I have now been asked about our flaggers, if they have to dig out the top soil etc at what point do we insist that they check for underground services? We do have instances where flags are simply lifted, the ground re-levelled and flags laid back down, equally we have situations where drives are flagged and therefore the ground needs to be dug out and hardcore laid prior to the flags etc. I do not want to go down the route of overkill, but equally am unaware of an industry standard or guidance that says this is best practice etc? Any help is gratefully appreciated.

Unless you have x-ray vision I would suggest that before you penetrate ANY external ground with any item you CAT SCAN the area –over the top? Quote from HSG (47) `This guidance applies to situations where underground services may be found and where work involves penetrating the ground at or below surface level. Buried services are widespread and it should be assumed they are present unless it has been shown otherwise’.