Archived - CIL: Evidence Base

Archived April 2016. This page will no longer be updated.


Which approach?

Before creating a Community Infrastructure Levy (CIL) you need to think about how you are going to do it, and who you need to employ to assist you.

You will also need to consider your approach to setting a CIL and plan-making at the outset. Your circumstances will determine your approach.

You, and anyone you appoint, need to understand the basic requirements for CIL, which are:

  • A development strategy for the area.
  • Enough information to prove that you need a CIL – aggregate infrastructure funding gap that is larger than the amount you seek to collect from CIL.
  • Viability evidence that you can use to ensure that your CIL  proposed rate or rates would not threaten delivery of the relevant Plan as a whole (National Planning Policy Framework paragraph 173)
  • to have a positive economic effect on development across a local plan area. When deciding the levy rates, an appropriate balance must be struck between additional investment to support development and the potential effect on the viability of developments.
  • State Aid rules related to CIL -  CIL should not be set to give any party a competitive advance .

If you are using a consultant for viability evidence they need to understand what your development strategy is, as your viability evidence should only focus on delivery of the development that forms your strategy (e.g. housing, agriculture and retail) – therefore it does not need to focus on offices, cinemas and ice rinks etc. if these are not relevant to delivering your strategy. You may want to do limited sampling if you think these uses have no viability and intend to zero rate them. You may also want to select a couple of sui generis uses that have been part of your growth in the past to test your rate and ensure that you do not harm future growth.

The advice produced by the Local Housing Delivery Group chaired by Lord Harman directly relevant to CIL and should be followed:


 (PDF 50 pages)

Questions to ask at the beginning of the process:

Are you going to employ consultants to:

  • do the lot?
  • manage the process, bringing together the different evidence streams, but get consultants to do your Infrastructure delivery plan, costings and viability evidence?
  • do the viability evidence?
  • do valuations for the viability appraisals and do the rest yourself?
  • do costings for infrastructure?
  • docostings for development?
  • to pull all the evidence together and critically review it ( CIL expert),  having  put some or all of the required evidence together?

You may also think about what you need for your plan making and what you already have and whether it can be used or refined.

What you definitely do not want to do is to procure something you do not need, does not do the job or that is too rigid and cannot meet your needs at the beginning, middle and end of the CIL setting and plan making process. You may have to do sampling of  larger sites, or more fine grain sampling if you decide to differentiate on geographic locations, type and/or size of development. The more differentiation the more likely you will be required to do more sampling. So think ahead and make sure your tender allows for iterations, sampling and refreshing and that the costs for these are clear. If your consultants are using a particular model – do you have rights to it? Will they teach your officers to utilise this model to test scenarios or undertake sampling?  Make sure you understand all the inputs into the model, and that it is transparent.

Procurement questions

When considering what approach you should take and whether to procure specialist help just for CIL, ask yourself what you already have, what you need/want and what you can realistically do yourself based the best use of skills and resources?

  • Do you already have an infrastructure delivery plan (IDP) or infrastructure list that supports the delivery of your local plan (core strategy)?
  • Is there enough information in your IDP to identify an aggregate funding gap that is greater than the amount of CIL you are likely to collect? If so, to set your CIL you may need no more in terms of infrastructure evidence. But you need to consider how this will be communicated and what you will do in terms of project managing the delivery of infrastructure when you have set your CIL.
  • Or do you need/want to demonstrate to councillors, the local community an aggregate funding gap that illustrates the IDP for the first five(?) years of the delivery of your strategy? In that case do you need further costing of infrastructure and too identify funding sources? ( this approach is referred to in many examinations)
  • Or do you need/want to demonstrate to councillors and the local community an aggregate funding gap based on all the major strategic infrastructure?
  • Do you understand, and have evidence about, the value of development and land across your area? This will have a significant impact on the rate/s you will set and whether you need to differentiate your rates in terms of geographic zones? Can you do a high level assessment of this with publically available information? Or is this the first stage that you would like a viability expert to do?
  • What do you consider a ‘competitive return' for the land owner will be on the different types of site required to provide for the development set out in your plan? Make sure your consultant discusses this with you and that you agree the  input into the model.
  • Do you understand the quantum of development that you are likely to be able to charge CIL and how much you may be able to achieve through CIL?
  • Make sure that you understand and agree all the key assumptions in the viability assessment. Make sure your consultant uses local values and costs.
  • Do you have up to date viability studies that you can use as a starting point to assess the viability of development in your area and help you define the assumptions for your assessment?
  • Can you reuse the inputs or models that you have already got for planning applications or plan making? Are they still valid? Make sure that the consultant is aware of the evidence you have (through application submission etc.) and is prepared to use it. 
  • Do you want a model and assumptions that you can reuse over time as circumstances or inputs change without re engaging the consultant?
  • Do you wish your consultant to be involved/arrange meetings/workshops with stakeholders to look at evidence, assumptions and different scenarios?
  • Is your consultant aware of your S106 history in terms of affordable housing and infrastructure contributions?
  • The examiner will ask you about your ‘buffer' or viability ‘cushion' – ask your consultant to determine the maximum Cil rate and then ask them to suggest the rate based on an appropriate buffer. (This might be achieved through an assessment of the market or based on the nature of the sites and in discussion with the development industry.)

Finally - just check

  • When you and your consultants consider viability for CIL you need to ensure that with your adopted CIL you can still deliver the development strategy for your area including the full policy level of affordable housing, and that you have balanced the desire to collect CIL for infrastructure while not putting too much development at risk. To achieve this, CIL viability cannot be considered in isolation – the other costs that will affect development in your area must be considered.
  • In any viability study, other policy costs such as affordable housing, sustainable carbon reduction measures, and potential s106 cost for site specific infrastructure to mitigate the effects of the development must be factored in. If you already have a plan, you need to ensure that you or your viability specialist is aware of these costs. If you are doing your plan in tandem with your CIL, emerging policy scenarios should be tested alongside emerging CIL rates to ensure that you achieve a balance that is viable and can deliver the development strategy for your area.
  • Make sure that you understand all the assumptions and information sources that have been used in your viability study, Avoid ‘black box' appraisal models.
  • Have you, and your consultants, used the ‘Viability Testing Local Plans: Advice for planning practitioners' in formulating your viability evidence? Be aware that the Examiner will use it.
  • When you are thinking of appointing any consultant make sure that they understand what you want them to achieve and for what purpose. CIL is fairly new and you need to make sure that your specialist consultant understands how their work will contribute to your CIL or wider plan making. Do not presume they understand what is required for CIL. 

Last updated 30 March 2015