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Hayley Mason

Senior Associate
Hayley Mason’s project and contract knowledge is superb and invaluable to the client. The project would not have progressed at the same pace if the Hayley’s knowledge and advice was not available to the client in such responsive manner.
Legal 500, 2020

Hayley advises procuring authorities, sponsors, funders and key supply chain members on major PPP, project finance and other forms of energy and infrastructure projects.

Many of the transactions Hayley has worked on have been innovative in the relevant sector, of particular note are the Welsh Government's flagship A465 Project and the Mersey Gateway Bridge PPP. Hayley has particular experience in not only closing major infrastructure projects, but also advising on the long term operational aspects and issues concerning such projects.

Hayley is recognised as a key lawyer in the Legal 500 Energy, Project Finance and PFI Sector.

Professional QualificationsSolicitor of the Senior Courts of England and Wales


  • Hayley was the lead Associate advising the Welsh Government in relation to its procurement of the Mutual Investment Model (MIM) £1.14 billion A465 Roads PPP Project to build, finance, operate and maintain a dual carriageway on Sections 5 and 6 of the A465 (Heads of the Valleys). Hayley was closely involved in every aspect of the Project including developing a new roads standard form project agreement, advice on procurement strategy; contributing to market "sounding" activity and analysis; development of the full suite of procurement documents; prequalification and down-selection; drafting and negotiation of all project documents; commercial and technical competitive dialogue; evaluation of tenders; preferred bidder announcement and financial close. Hayley continues to advise the Welsh Government on the construction phase of the Project.
  • Hayley advised the procuring authority, Halton Borough Council, on the procurement of the Mersey Gateway project. The project is a major scheme to build a new six-lane toll bridge over the River Mersey that will relieve the congested and ageing Silver Jubilee Bridge. The scheme has a capital cost in excess of £500 million and will be the first new road in the UK funded through open road tolling. Hayley continues to advise the Mersey Gateway Crossings Board in relation to operational matters concerning the Project.
  • Hayley has advised in relation to a number of projects relating to the improvement of energy efficiency, district heat networks and reduction of carbon emissions from public sector buildings. These projects include energy upgrade works and provision of heat, electricity, steam and cooling and long term operation and maintenance. The projects are funded by the guaranteed savings from the decrease in energy consumed and/or through designated public sector grant funding.
  • Hayley has recently advised in relation to a number of projects funded by the BEIS Public Sector Decarbonisation Scheme. These projects utilise innovative new technologies, including battery storage, solar PV cells, and water and air source heat pumps.
  • Hayley also advises a number of clients in the nuclear sector. Highlights have included advising General Electric in relation to EDF’s acquisition of GE Steam Power’s nuclear activities, and advising in relation to nuclear new build projects in Abu Dhabi and Saudi Arabia.
  • Hayley has undertaken a secondment to the Department of Business Energy and Industrial Strategy ("BEIS") to support the BEIS legal team with their preparations for Brexit. Hayley worked with the Energy Efficiency, Heat and Climate Change and Energy Development Teams to review and analyse domestic and EU legislation to assess the potential inoperabilities of such legislation following the UK's exit from the European Union.
  • Durham University, BA (Hons)
  • University of Law, GDL and LPC - Distinction