The role of an ecological clerk of works
Supervising ecological mitigation on site only works when the condition, the construction management plan and the building contract line up. What to specify.
An ecological clerk of works has no statutory power to stop anything. Whatever the planning condition says, the authority to halt a machine comes from the construction contract, and if nobody wrote it in, the ECoW is a person in a high-visibility vest making suggestions.
That is the practical starting point for anyone budgeting the ecological clerk of works role on a scheme with protected species or a habitat retention obligation. The appointment is worth having. It only works when the site set-up gives it teeth.
What the role covers on site
The ECoW supervises the delivery of ecological mitigation during construction. The work is specific and it is different from the work of the ecologist who wrote the assessment.
A typical scope:
- Pre-works checks of buildings, trees, ponds and vegetation immediately before clearance.
- Supervision of soft-felling, soft strip and demolition where roosting or nesting features are present.
- Marking and checking exclusion fencing, buffer zones and root protection areas.
- Toolbox talks and inductions so that operatives know what to stop for and who to call.
- Supervising the installation of mitigation features such as bat boxes, hibernacula, newt fencing and hedgehog gaps.
- Recording compliance for the discharge of conditions and for any licence return.
- Responding when something unexpected is found, which on most sites happens at least once.
The last item is the reason the role exists. Method statements describe the site as surveyed. Contractors encounter the site as it is.
Competence and licensing where protected species are present
Competence for an ECoW is judged on species experience rather than on a job title. The usual reference point is membership of the Chartered Institute of Ecology and Environmental Management at an appropriate grade, together with demonstrable site experience of the species in question.
Where a licence is involved the position is stricter. Works affecting European protected species need a licence under the Conservation of Habitats and Species Regulations 2017, and works affecting species protected under the Wildlife and Countryside Act 1981 may need one under section 16. A licence names the ecologist responsible, and only that person or an accredited agent working under them can carry out the licensed operations.
Class licences work differently again. A registered consultant under a bat or great crested newt class licence has to hold the registration personally, and a general ECoW appointment does not confer it.
Three questions to ask before appointing:
- Which species will this person be supervising, and what recent site experience do they have with each?
- Do they hold, or are they named on, the licence that covers the works?
- Who covers their absence, and does the cover hold the same licence?
The third question is the one that fails on real sites. A single named ecologist on holiday during demolition week stops the job.
What competence means as a legal test differs between regimes, and the comparison is set out in what competent person means in planning legislation.
Authority to stop works and how it is secured
Three documents have to line up.
The planning condition should require works to be carried out in accordance with an approved construction environmental management plan, under the supervision of a suitably qualified ecologist, with a named stop-work procedure.
The Construction Management Plan should then set out that procedure in operational terms: who the ECoW reports to, what happens when works are halted, how long a halt may last before it is escalated, and who bears the cost.
The construction contract has to give effect to it. Without a contractual instruction route, the site manager can decline and the ECoW's only recourse is to report a licence breach after the event.
Get the stop-work clause into the contract before works start. Retrofitting it into a signed contract during a bat emergence is not a negotiation anyone wins.
Reporting lines and record keeping
Reporting to the contractor alone creates an obvious conflict. Reporting to the client, with copies to the contractor and a duty to notify the local planning authority of any breach, is the arrangement that holds up.
Records the ECoW should keep, dated and site-specific:
- A site diary of every attendance, with the works supervised and any instruction given.
- A photographic record of features before and after works, and of installed mitigation.
- Toolbox talk registers with signatures.
- Incident records, including near misses, with the action taken.
- Licence returns where required, submitted within the period the licence specifies.
Licence returns are the item most often missed. A missed return is a licence breach, and it affects the ecologist's ability to obtain the next one.
Frequency of attendance in a condition
Conditions that specify attendance by activity work better than conditions that specify a number of visits.
| Activity | Attendance expectation |
|---|---|
| Vegetation and scrub clearance | Immediately before, and supervision throughout on sensitive sites |
| Soft strip and demolition of a building with roosting potential | Full supervision, with the roost features taken down by hand |
| Pond infilling or works within a newt exclusion area | Full supervision |
| Groundworks within a buffer zone | Spot checks with a stated minimum frequency |
| Installation of mitigation features | Attendance and sign-off |
| General construction | Periodic audit visits at a stated interval |
The Protected Species Survey and the mitigation strategy should drive that schedule, and a licensed ecologist is legally required for the survey work and any mitigation licence under the 1981 Act and the 2017 Regulations. A PlanScope draft is a starting point for that ecologist rather than a substitute for their work.
Budget realistically. Attendance is priced per visit, mobilisation on a rural site can exceed the time on site, and an underpriced appointment produces an ECoW who arrives late and signs off from the van.
Coordination with the construction manager
The relationship that determines whether this works is between the ECoW and the site manager, and it is built before the first delivery.
Practical measures: put the ecological constraints on the site layout drawing that the operatives actually use, not in an appendix. Programme the seasonal constraints into the master programme as fixed windows rather than as notes. Agree a single point of contact and a response time. Include the ECoW in the weekly progress meeting during sensitive phases.
Where the ECoW is treated as an auditor who turns up to find fault, the site works around them. Where the ECoW is part of the team planning the week ahead, problems get raised before the machine moves. That difference costs nothing and saves more than any other measure on this list.
Reviewers who can check a mitigation strategy or an ECoW scope before it is submitted can be found through the professional directory.
Securing the role through a planning condition
Wording that works names four things: the qualification expected, the activities requiring attendance, the reporting obligation, and the trigger for the final report.
Wording that fails says that an ecological clerk of works shall be appointed, with no scope, no attendance schedule and no reporting duty. That condition is satisfied by appointing anyone at all.
Where biodiversity net gain applies, the construction-stage supervision is separate from the habitat management and monitoring obligations that run for 30 years under the Environment Act 2021 regime. Do not let a condition conflate them, because the skills, the duration and the funding are different. The statutory metric and the gain plan need a competent person, and the ECoW may or may not be that person.
One honest uncertainty: there is no register of ecological clerks of works and no single accreditation for the role, so the appointment rests on references and on the species licences the individual holds.
This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Enter your postcode on PlanScope to see which ecology documents a site is likely to need before works start.
Frequently asked questions
Can an ecological clerk of works stop construction?
Not by statute. The authority comes from the construction contract and the approved construction environmental management plan. Write a stop-work procedure into both before works start, naming who the ECoW instructs, how long a halt may run before escalation and who bears the cost, otherwise the role has no practical power.
What qualifications should an ECoW hold?
Membership of the Chartered Institute of Ecology and Environmental Management at an appropriate grade, plus recent site experience of the species being supervised. Where a licence is involved, the individual must be named on it or hold the relevant class licence registration personally, because a general appointment does not confer licensed status.
Is the ECoW the same person who wrote the ecology report?
Often, but it does not have to be, and there is an argument for separation. The assessment author knows the site and the mitigation logic. A separate supervisor brings independence, which matters where the client is also the contractor. What cannot be separated is licence responsibility, which stays with the named ecologist.
How often should an ECoW attend site?
Tie attendance to activities rather than to a visit count. Full supervision is needed for soft strip of a building with roosting potential, pond works and newt exclusion areas. Add pre-works checks before vegetation clearance, spot checks within buffer zones, and periodic audit visits during general construction at a stated interval.
What records should be kept?
A dated site diary of every attendance and instruction, a photographic record of features before and after works and of installed mitigation, signed toolbox talk registers, incident and near-miss records, and any licence returns submitted within the period the licence specifies. Missed licence returns are themselves a breach.
Does appointing an ECoW transfer legal liability?
No. Offences under the Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017 can be committed by the developer, the contractor and individual operatives. Supervision reduces the risk of an offence occurring; it does not move responsibility away from the parties carrying out the works.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.