Take 5: Planning to demolish? We'll level with you

The law on demolishing a building is not as straight forward as it might seem. There has been a flurry of recent court cases on demolition, so it's a good time to recap on how to flatten your site without being bulldozed by the law. What can we learn from these decisions? What should you look out for or avoid? Read on for our 5 top tips:

1. Do you have planning permission?

This is crucial. Demolition is a type of "development" under the planning rules and so, as with other types of development, it is an offence to carry it out without planning permission. As the recent Sam Smith case shows, even if the council requires you to demolish the building because it is unsafe, planning permission for its removal is still needed, although being required to pull it down for health and safety reasons could be a defence.

Planning consent for demolishing a building can take different forms and there are exemptions for small buildings (less than 50 cubic metres) and other structures in certain circumstances. If you do not have express planning permission for the demolition you may be able to use permitted development rights, but be careful: the rights don't apply to all buildings and are subject to conditions and limitations which must be complied with.

2. Is the building listed or in a conservation area?

If the building is listed (or is in the curtilage of a listed building),a separate listed building consent will be needed.

Pubs, concert halls, theatres and live music venues have special protection even if they are not listed, as do statues and memorials that have been in place for ten years.

If the property is in a conservation area, the permitted development rights will not apply either, so you will need to apply for planning permission. Watch out for changes to conservation area boundaries. In the Future High Street Living case, the council widened the conservation area to include the building after the prior notification application needed to use the permitted development right was submitted, so the permitted development right could not be relied on.

Remember that permitted development rights can be disapplied in certain areas by Article 4 Directions so double check that you are not caught out by one of those if you are intending to rely on the permitted development right.

3. Will the demolition affect your CIL liability?

If you are demolishing in order to clear the site for redevelopment, be mindful of how this might affect your CIL liability for the new buildings. Sometimes it is possible to reduce your CIL liability by deducting floorspace of "in use" buildings. There are timing constraints over whether a building qualifies as an "in use" building, so it is important to consider when to carry out the demolition. Delaying the demolition could save you thousands.

4. Are you demolishing to save your planning permission?

All planning permissions have an expiry date and must be "implemented" before the deadline to keep them alive. Implementation is secured by the carrying out of a "material operation comprised in the development".

What does this mean? Common examples of material operations to secure implementation are digging a trench for foundations or laying the utility pipes. It is essential that the works match what has been approved by the planning permission. In other words, that they are consistent with the approved drawings.

The law specifically lists demolition of a building as a material operation. In the recent Atwill case, demolition works were relied upon to argue that a planning permission had been kept alive. However, as was illustrated by this case, it can be difficult to show how the demolition works are part of the approved development. In this case, the building works that followed the demolition were not carried out in accordance with the same planning permission. This certainly didn't help the case for lawful implementation by demolition. As what was eventually built was so different to that permitted by the original planning permission, the judge was not convinced that the demolition related to the permission and therefore the planning permission was not kept alive by the demolition works.

The main takeaway here is that in order to rely on demolition as implementation, you need to ensure that (a) demolition is authorised by the permission in question (ideally included in the description of development) and (b) what is eventually built accords with the permission. An agreed demolition plan or demolition related conditions can help, but in the absence of these, it is safer to carry out a material operation which matches up with approved plans to show that is clearly comprised in the development.

5. Have you triggered any planning conditions, obligations or CIL?

If your planning permission does include demolition works, be mindful that the local planning authority may take those works to mean that you are implementing a planning permission even if that isn't your intention.

Check the planning conditions and any accompanying Section 106 agreement to see if demolition works are carved out so that any conditions/planning obligations are not triggered. If the relevant planning permission is caught by the Community Infrastructure Levy, you may wish to make a minor amendment to the permission so that demolition is excluded if you can use permitted development rights to demolish instead.