1984 cable depth Regulation / legislation - New to forum

[JK01]

Hi, cable breached on site. Northern power advised no legislation re depth of cable in existence (holding me liable). Is this correct? Cable found at 170mm below surface.
can anyone provide any document stating 1984 cable depth legislation, and any associated depth legislation?
CAT scan used however soft dig not possible due to cement / brick area.

 

[Sintra]

Is it a HV or LV cable?

 

[Darkwood]

What is the nature of the land, is it private or public, was it documented on site plans and TBH 170mm is shallow in the scope of things 500mm to 600mm is somewhere about the ball park depth with a warning tape approx 150mm not the cable.. this has been the case as long as I recall even as far back as that.

If the use of the land, an agreement + documented plans were done then you may have a case as a failure for these plans to be forwarded to other contractors digging the site could be your argument but that's a lot of ifs and buts there.

Are you Insured for such events?