Trench warfare

60 ft long and three feet deep. It used a JCB360 with a one foot-wide bucket. It wasn't the biggest civil engineering job in the world, but the digger driver and banksman were taking care because they knew that a hefty electricity cable ran across their intended dig. They found it.

There was a loud bang "like a gunshot" said the digger driver; his bucket had severed three live cables. The London Electricity Board sent the builder a bill for £128 000 – the expense, it said, incurred bringing in a jointing team, materials and two well-known specialist contractors, McNicholas and Balfour Kilpatrick. The bill also included a general overhead charge under the heading of damages.

Quattro, of course, agreed it had severed the LEB's cable, but insisted, nevertheless, that it had taken all reasonable care and so had not been negligent. It also thought the bill was too high.

It is interesting to read exactly what care a court thinks a builder should take in practical terms. Let's face it, a digger of yours out on site right now could easily be about to cost you a packet … enough to put a dimple in the profits or a broadside in the balance sheet.

Apparently, the lads on site looked up the LEB plans drawn six years ago. Good start. But by now, several buildings on the plan had been demolished and ground levels had been raised, so the plans were difficult to use; a very ordinary problem.

Sensibly, the lads reached for a CAT detector. It was marched up and down the proposed line of dig, but nothing registered to show a cable. They knew from previous experience that cables were somewhere below and that they were covered by concrete tiles.

So despite no signal from the CAT, they carefully began the dig, with the banksman watching the bucket at soil level, ready to signal to the digger driver if an obstruction arose. Are they being careful enough so far?

Then the bucket hit an obstruction. The banksman signalled a stop and climbed into the shallow trench. None of the normal signs was there; no sand, no warning markers, no cable trough and no tiles. So, he signalled to the digger driver to take out the obstruction. That's when the loud gunshot sound went off. They had ripped out the cables.

Let’s face it, a digger of yours out on site right now could easily be about to cost you a packet – enough to damage profits

Can you criticise the builder? The judge did – London Electricity plc vs Quattro UK Ltd – and found that it was negligent. He read the Health and Safety Executive publication, Avoiding Danger from Underground Services, which he described as little more than common sense.

The HSE recommends using cable-locating devices and urges that plans be studied. So why did the judge rule against the builder? He thought that the builder failed to use the CAT detector to its full capacity, stating that it should have been used during the digging, in particular when an obstruction was encountered. He found that these two precautions were missing and therefore the builder's behaviour fell below the acceptable standard of care.

So what is payable? This is not a claim under a contract, but rather a claim by the owner of the cables for damage done by a stranger. In such a case, only the costs arising directly from the need to repair physical damage are claimable.

Balfour Kilpatrick was engaged by the LEB to dig out the damaged cables and fit replacements and McNicholas provided labour and plant; the judge was persuaded that this highly specialised work justified £77 000 costs. Justified too was another £29 000 for the materials for six joints.

But the judge disallowed LEB's inclusion of a 10% uplift on its contractors' invoices to cover the administration costs involved in running any business enterprise, as a claim in negligence must relate to expense arising from the repair of physical damage to the property (An example would be the overhead costs of supervising the repair, as compared with everyday overheads).

There is little doubt that the LEB had particular overhead costs in relation to the repair, but it did not put the case in these terms, so the overhead claim failed for want of proof.

The judge also disallowed costs for maintenance work.