Permitted development does not excuse a wildlife offence

Permitted development rights give you planning permission. They do not give you a defence to a wildlife offence. If there are bats in your loft, converting it under Class B of the Town and Country Planning (General Permitted Development) (England) Order 2015 is still lawful development and can still land you with a criminal prosecution, because permitted development and bats sit under two completely separate statutes. The Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017 operate regardless of whether a planning application was needed, and the offences they create apply to the person doing the work.

Why a planning right is not a defence

Planning control and wildlife protection are different regimes with different enforcement bodies. The local planning authority administers the first. The police and, for licensing, Natural England deal with the second.

Nothing in the General Permitted Development Order disapplies wildlife law. A prior approval that has been granted, a lawful development certificate confirming your extension is permitted development, even a full planning permission: none of them authorise disturbing a bat roost or destroying an active bird's nest.

That surprises people, and it surprises builders more. On a householder project the homeowner, the contractor and anyone who instructed the work can all be exposed, because the offences attach to the act rather than to ownership.

Where a full planning application is made, the council has a duty to consider protected species as part of the decision, which is why ecology reports appear on application files. On a permitted development project nobody does that check for you. You have to do it yourself.

Bats and the roost offence

All bat species in the United Kingdom are European protected species. Under the Conservation of Habitats and Species Regulations 2017 it is an offence to deliberately capture, injure or kill a bat, to deliberately disturb a bat in a way that affects its ability to survive, breed or rear young, and to damage or destroy a breeding site or resting place.

The last of those is the one that catches householders, for two reasons. It does not require intent in the way the disturbance offence does, and a roost remains a roost whether or not bats are present at the time. A loft used by a small number of bats in summer is a resting place in January as well.

The works most likely to affect roosts are loft conversions and dormers, re-roofing and replacing felt with a breathable membrane, soffit and fascia replacement, repointing or rendering, removing hanging tiles or weatherboarding, demolishing outbuildings, treating timber, and installing insulation in a roof void.

Tree works matter too. Mature trees with cavities, splits and lifting bark can hold roosts, and felling them is subject to the same offences. If a tree is also protected by an order, you have two consent regimes to satisfy rather than one, and the arboricultural information from a Tree Survey should flag the features that need checking.

Nesting birds and the timing of roof work

All wild birds, their nests while in use or being built, and their eggs are protected under section 1 of the Wildlife and Countryside Act 1981. The offence is to intentionally take, damage or destroy a nest that is in use or being built, so timing rather than licensing is usually the answer.

The main breeding season runs from March to August, with some species nesting earlier and later, so the standard precaution is to avoid works to roofs, soffits, hedges, scrub and ivy-covered walls during that period. Where work has to happen in season, the usual route is a check by an ecologist immediately before work starts, with any active nest left undisturbed and a buffer maintained until the young have fledged.

Swifts, house martins and house sparrows nest in the fabric of buildings and are easy to miss. Swift nests sit behind soffits and under eaves and give almost no external sign other than birds entering at speed. Sparrow colonies under roof tiles are similarly invisible from the ground.

Replacing felt with a taut membrane removes the cavity those species and bats rely on, which is why a re-roof that looks like pure maintenance can end a colony that has used the building for decades. Some external alteration work sits under Part 2 of the Order, and the limits are set out in painting and external alterations under Part 2.

Checking before work starts

The check is proportionate to the building and the work. For most householder projects it is quick and inexpensive compared with the cost of stopping.

1. Look for the signs yourself. Droppings on walls, soffits or in the loft, staining around gaps at the eaves or ridge, insect wings below a roosting point, birds entering the roof line at dusk or in spring, and bats emerging at dusk in summer.
2. Check whether there is a known roost record for the property. Local records centres hold species records and some are searchable.
3. Where the building has any of the risk features, commission a preliminary roost assessment. This is a daytime inspection of the building and its surroundings and can be done at any time of year.
4. If the assessment finds evidence or moderate to high roosting potential, emergence and re-entry surveys follow. These are seasonal: May to September, with May to August the better window.
5. Allow for the season in the programme. A project that discovers in October that it needs emergence surveys waits until the following May.

A Preliminary Ecological Appraisal covers the wider site where there is habitat as well as buildings, and a Protected Species Survey is the specific piece of work for a confirmed or suspected roost.

Note: an assessment carried out before the scaffolding goes up costs a fraction of one carried out after a roost has been damaged, and it also protects the people doing the work.

What to do if bats are found mid-works

Stop. Not later in the day, not at the end of the lift.

Then take three steps. Leave the area undisturbed and do not attempt to move an animal. Get advice from an ecologist with a bat licence, or contact the national bat helpline run by the Bat Conservation Trust for immediate guidance. Record what was found, where and when, with photographs taken from a distance.

Resuming work needs the position assessing properly. If a roost is confirmed and the works will damage it, a licence is required before the works continue. Carrying on and hoping is the decision that turns an inconvenience into a prosecution, and discovery is common because neighbours notice bats.

Licensing routes and who applies

Where works will affect a roost, the route is a European protected species mitigation licence from Natural England, or, for lower impact cases, a class licence held by a registered consultant that allows certain works to proceed under a registration rather than a full licence application.

Several points about licensing are worth knowing before you start.

The licence is applied for by, or through, a suitably licensed ecologist, and the application has to be supported by survey work, an impact assessment and a mitigation and compensation plan, typically including replacement roosting provision such as bat boxes, access gaps or a dedicated void.

Surveys and any mitigation licence require a suitably licensed ecologist under the Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017, so this is one report type where professional involvement is legally required rather than advisable. An AI-assisted draft is a starting point for that ecologist and not a substitute for the survey.

Timing is the practical constraint. Survey season, licence determination and the mitigation design sit in sequence, and a project that leaves this to the last minute loses a building season.

Recording the check

Keep the evidence even where nothing is found. A dated preliminary roost assessment report, photographs of the loft and eaves before work, the ecologist's name and licence number where one was involved, and a note in the site diary of the pre-start check.

That file does two things. It demonstrates the due diligence that matters if a question is raised later, and it gives the contractor a clear instruction about what to do on discovery. Put the stop-work instruction in writing to whoever is on the roof.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. Enter your postcode on PlanScope to see which reports your site needs. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.