Solent Disturbance Mitigation Project (SDMP)

All applications for planning permission or prior approval for new residential development across the city received after Monday 7 July 2014 need to provide a means of mitigating the development's impact upon the ecological importance of the Special Protection Areas within and around the Solent.

Whilst applicants may propose alternative measures to mitigate the direct impact of their development on the Solent SPA, the simplest way of mitigating will be through the Solent Disturbance Mitigation Project.

Please note that as a result of annual indexation, the SDMP contribution will be increasing from £176 to £181 per residential unit for all planning applications made valid on or after the 1 April 2017.

This requires applicants to either:

  • Make a financial contribution of £181 per dwelling either before planning permission is granted or by completing the SDMP Agreement and sending the completed form along with mitigation contribution to the Planning Agreements Officer at the Local Planning Authority. 


  • By completing the Unilateral Undertaking before planning permission is granted with an undertaking that the payment of £181/dwelling will be made before the development is implemented. Please note that on submission of the Unilateral Undertaking, to the Planning Agreements Officer at the Local Planning Authority, a £75 fee/cheque will also need to be submitted to cover checking fees by the council's legal team. 

Apply for mitigation

Please choose one of the following options:

SDMP Agreement Fill in the Habitats Mitigation Contribution Agreement and submit to the Local Planning Authority, along with the SDMP Mitigation Contribution of £181 per residential unit.

Unilateral Undertaking Fill in and submit the council's standard Unilateral Undertaking with the planning application, along with the £75 checking fee.

For either option please submit the necessary information to the Planning Agreements Officer early enough to ensure the application process isn't delayed or refused.

Further information on the calculation/setting of the £181 is available from the Appendix to the Interim Mitigation Framework.

Further details of how the contributions will be collected and spent are set out in the attached documents and further information regarding the SDMP can be found on the Portsmouth Solent Disturbance and Mitigation Project site. If your enquiry relates to a specific application case please contact the planning case officer, or phone the duty planning officer on 023 8083 2603.