Principal Contractor and Contractor Duties – Clause-by-clause comparison of the CDM 2015 Regulations and CDM 2007


CDM Principal Contractors & Contractors duties – Comparing the changes in the CDM 2015 Regulations and CDM 2007

Download a note prepared by Mike Webster that identifies, clause-by-clause, the changes in the Principal Contractor and Contractor duties in the CDM 2015 regulations compared to those in CDM 2007, so making it easier to comply.


The Construction (Design and Management) Regulations 2015 (CDM 2015) govern the management of health, safety and welfare when undertaking construction projects in Great Britain.  CDM 2015 replaced CDM 2007 on 6 April 2015.

The eight key changes to the CDM 2015 Regulations from CDM 2007 are:

  • The CDM 2015 Regulations have a simplified structure
  • Clients' responsibilities have been strengthened and broadened
  • The exemption for Domestic Clients has been removed
  • The role of CDM Coordinator has been removed
  • The new role of Principal Designer has been introduced to plan, manage, monitor and coordinate the pre-construction (design) phase
  • Notification of the project to the Health and Safety Executive (HSE) has been removed as a trigger point for additional duties
  • The threshold for appointing a Principal Designer and Principal Contractor is if more than one Contractor is required on a project
  • The requirement for 'competence' has been removed and replaced with 'skills, knowledge, experience and training' and 'organisational capability’

To read a brief summary of those eight key changes and what they mean in practice, click here.

To read a summary of published discussions and answers to a range of frequently asked questions click here.

A series of articles providing information on key issues regarding the CDM 2015 Principal Designer duties are collected together for ease of use in this post.

Detailed changes have been made to the clauses of the CDM Regulations themselves.  To capture these changes, I have prepared a document containing a clause-by-clause comparison of the Principal Contractor and Contractor duties in CDM 2015 and CDM 2007. This allows all of the changes to be identified, including the relatively subtle changes to the wording of the Regulations, so that you can make the necessary changes to your practice.

This is the third document in this series, following on from the comparison of Designer duties and Client duties.

This document may be subject to change as more information becomes available.  If you let me have your email address I will notify you when updated versions and other relevant CDM 2015 material are available.

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About the author:

Dr Mike Webster is a chartered civil and structural engineer with over 30 years' experience including ten years' at director level.  He founded MPW R&R to provide Consulting, Forensic and Expert Witness services for Construction and Structural Safety, CDM and Risk.

Mike led a review of CDM 1994 and the independent evaluation of CDM 2007 for the Health and Safety Executive.  He reviewed the use of CDM 2007 in the construction of London 2012, and has acted as an expert witness in criminal prosecutions regarding breaches of the CDM Regulations (CDM 1994, CDM 2007 and CDM 2015).  He is the author of around 20 published reports and papers on construction health and safety and the CDM Regulations.

Mike can provide advice or training on CDM 2015, or work with you in your organisation to implement changes.  If there has been an incident on site that is heading to dispute or litigation, he would be willing to act as an expert witness.

For more information drop Mike a line at or give me a call on  07969 957471.



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