Striking buried services is still one of the fastest ways to injure people, halt programmes and burn through contingency on UK sites. Too often the permit-to-dig is produced, signed and filed while the real controls stay in the cabin. If the permit is to earn its keep, it has to translate drawings and surveys into paint on the ground, clear authorisations, and line-of-sight supervision at the point of work. The aim is not paperwork; the aim is to put time, distance and certainty between plant, spades and live services.
TL;DR
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– Treat the ground as energised until you’ve proved and marked what’s there, not just what the plan says.
– Tie the permit to a live brief, a visible mark-up, and a named supervisor with stop-work authority.
– Repeat scans, re-brief and re-authorise whenever the set-up, weather or shift changes.
– Keep people and plant apart; keep method and pace appropriate near tolerance zones.
– Close out properly: update records, remove or refresh markings, and capture lessons for the next dig.
Turning permits into control: the playbook
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Define the scope, red lines and competence before mobilisation
Get the basics framed early: what’s being dug, where the limits are, and what services are suspected or known. Decide what level of utility detection survey you need based on risk, ground type and congestion; push for quality data, not just old records. Confirm who is competent to locate services and who is authorised to issue and hold the permit. Build the method around the highest-risk interfaces: adjacent live assets, temporary works needs, traffic routes and public boundaries.
# Prove the information: plans, locate, trial, then decide
/> Treat utility drawings as a start point, not the truth. Use appropriate locating equipment (CAT and signal generator as a minimum) and, where complexity or uncertainty exists, bring in ground-penetrating radar or specialist surveys. Mark out on hard surfaces and soft ground with durable paint and pins, noting depth indications cautiously. Trial holes by hand or vacuum excavation to confirm actual positions and depths within tolerance zones. Record what you find; if it doesn’t match the plan, stop and reconcile before you dig on.
# Make the controls visible: mark-up, brief and permit at the point of work
/> The permit should name the area, limits, identified services, tolerance zones, and the method and plant allowed. Put the paperwork and the mark-out side by side at the dig face during the brief. Walk the team around the markings and explain the no-go strips, hand-dig zones, safe plant positions, and spoil areas. Confirm emergency arrangements and who can say stop. Time-limit the permit and explicitly tie it to today’s conditions, today’s crew and the current layout.
# Execute slowly and deliberately: supervise the dig, not the paper
/> Near services, pace is a control. Keep a competent supervisor present and visible when breaking ground or working within tolerance zones. Use hand tools with insulated shafts where needed; set plant with the bucket pulling away from marked services, not over them. Maintain segregation and banksman control; exclude non-essential people. As levels change, reassess shoring, edge protection and ingress of water. If anything deviates—plant swap, weather shift, markings disturbed—pause and re-authorise.
# Close out and hand back: tidy, record and learn
/> When the dig is complete or paused for longer than a short break, close the permit. Remove or refresh markings to avoid misleading future teams. Update site records with confirmed service positions or anomalies found. Photograph the mark-out and trial holes with references that will make sense to the next supervisor. Feed lessons learned into the next permit, especially around congested areas, uncharted services and sequencing clashes with other trades.
Scenario: night-time slot trench on a live high street
/> A streetscape team is cutting a 300 mm slot trench to install new lighting ducting along a busy high street. The area is known to be service-heavy, and the programme has been squeezed to fit night shifts. The permit is prepared in the afternoon using current utility plans; the supervisor and locator meet on site at dusk to scan and chalk up the route, picking up a gas main not shown where expected. They hand-dig trial holes at three crossings, adjusting the trench line by 200 mm to maintain separation. A mobile MEWP for sign works is planned to pass the trench edge; the team adds barriers and a banksman to keep plant out of the no-go zone. Rain starts; markings begin to wash, so the supervisor pauses cutting and re-marks under temporary plastic sheeting. At 02:00 a new crew arrives for the second half of the shift—no one breaks ground until the supervisor re-briefs and re-validates the permit against the lived conditions.
Common traps that devalue a permit-to-dig
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Issuing from the desk, not the dig face
Permits written without a physical walkover produce blind spots and misaligned boundaries.
# Treating one scan as “job done”
/> Ground conditions, signal coupling and interference change; repeat scans at key stages and after breaks.
# Vague markings and no photos
/> Faded paint and no recorded references lead to guesswork later in the shift or on the next visit.
# Permit drift through shift changes
/> Authorisation needs to follow the people and the plant; re-brief and re-sign when teams rotate.
Pre-break-ground checklist for supervisors
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– Verify the latest utility records are on hand and match the area to be dug.
– Confirm locator competence, calibration of locating kit, and method for proving services.
– Walk the line: durable mark-up of services, tolerance zones, dig limits and exclusion boundaries.
– Brief at the point of work: method, plant allowed, hand-dig areas, banksman roles, and stop triggers.
– Set physical controls: barriers, signage, lighting, shoring plan, spoil placement and traffic routes.
– Tie authorisation to time and team: permit displayed at the dig, with end-of-shift expiry.
– Establish contingency: emergency contact numbers, isolation routes and escalation path.
Bottom line: make the permit live where the spade meets the ground
/> A permit that controls who digs, how they dig, and where they stop is worth more than any stack of laminated drawings. The essentials are simple: prove, mark, brief, supervise, and pause when reality doesn’t match expectation. The minute the permit becomes a comfort blanket rather than a control, you’re back to chance.
# What to nail down before next Monday’s digs
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– Line up competent locating resource and book them early where you’ve got congested corridors.
– Agree how you’ll protect and refresh mark-up in wet, dark or high-traffic conditions.
– Decide your default near-service method (hand or vacuum) and when mechanical excavation is acceptable.
– Set a clear, site-wide stop-work trigger if markings are unclear or plant changes mid-dig.
– Build in time for trial holes and re-briefs; don’t push pace at the edge of a gas or HV corridor.
Utility owners and principal contractors alike are paying closer attention to how permits function in practice, not just on paper. Expect more questions about competence, proof of mark-up and how you supervise the first bite; have your answers ready on site, not back in the office.
FAQ
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When do we actually need a permit to dig?
Whenever breaking ground could bring you into contact with buried services, structures or unknowns, a permit is a simple way to lock in controls. Treat it as standard near utilities, near existing buildings, and in public interfaces. It helps coordinate surveys, briefings and supervision so everyone knows the limits and method before the first cut.
# Who should issue and hold the permit on site?
/> A competent person who understands the ground risks, the method and the layout should issue it, often the site manager or an authorised supervisor. The person in charge of the dig should physically hold it at the point of work so they can enforce stop/start decisions. Make sure authority is clear if shifts change or plant swaps mid-task.
# How often should we rescan during a dig?
/> Rescan at the start of each shift, after layout changes, when you move into new ground, or if you lose confidence in the markings. Interference, weather and different plant positions can alter what the locator picks up. Build rescans into the method rather than waiting for a near miss to justify the pause.
# What if mechanical excavation is unavoidable near a suspected service?
/> Build in additional controls: define a hand-dig buffer, use a smaller bucket, pull away from the marked line, and reduce speed. Consider vacuum excavation and trial holes to prove locations before putting teeth in the ground. Keep a competent supervisor and banksman engaged, and be ready to stop if conditions don’t tally with the plan.
# How do permits link with temporary works and traffic management?
/> Permits should reference any shoring or support requirements and who has designed or approved them. They should also map how plant and pedestrians are kept apart, including banksman positions and exclusion zones. Good housekeeping matters too—spoil, tools and barriers need planned placement so they don’t push people or plant into the tolerance zones. If controls can’t be maintained, escalate and re-plan before digging further.
