Sam O’Callaghan (Capital Law)

Sam O’Callaghan

Principal Associate
Construction, Energy & Projects

Sam O’Callaghan is a Principal Associate in the Construction, Energy & Projects team, with expertise in complex contentious construction matters.

Sam was called to the Bar in 2014 before joining a construction law consultancy specialising in out of court dispute resolution (both nationally and internationally). Since starting at Capital, Sam has also qualified as a solicitor.

Sam has expertise in all forms of dispute resolution relevant to large construction / commercial disputes, with a notable focus on construction adjudication.

He has assisted clients throughout the supply chain, from funders, to employers, to contractors and specialist sub-contractors, covering both public and private sector clients. The experience of resolving disputes gives Sam unique insight on potential problems that need to be dealt with contractually. This helps with Sam’s contract drafting and negotiation offering.

Sam’s had articles and comments published in publications such as The Guardian and has appeared on BBC Radio Wales to address the ramifications of Carillion’s collapse.

Sam O’Callaghan is a phenomenal construction lawyer. He has in-depth knowledge on a wide variety of construction contracts. Sam leaves no stone unturned.

The Legal 500 2023

  • Advising Ceredigion County Council on the “Cylch Caron” scheme, with Welsh Government as funder, providing full legal services in appointing a Delivery Partner for an ambitious Extra Care Facility project in collaboration with the local NHS health board. The project aims to provide a purpose-built centre for integrated delivery of health and social care services together with specialist housing for individuals with care needs.
  • Advised FE college on procurement and contractual documentation for the £30million Science, Technology, Engineering, Arts and Mathematics (STEAM) Academy that was procured and funded under the 21st Century School funding stream (MIM).
  • Commenced and defended several complex Adjudications on behalf of a contractor against a local authority – with the local authority claiming £14million for alleged defects.
  • Legal advisor to a pan-Wales project (funded by Welsh Government) which aims to deliver a long-term treatment/recycling solution for absorbent hygiene product (“AHP”) waste across Wales (including items such as nappies and personal care wipes). The advice to date involved project structuring from full solution based on MIM / PFI Agreements to splitting the project into work packages – covering the technology solution through to haulage of the AHP waste to the reference sites (and including service level agreements and commercial agreements for the operation of the AHP plant).
  • Assisting a large repair and maintenance contractor with a £3million aged debt claim which was met by over £4million counterclaim. Involved 7 discrete Adjudications before being resolved by negotiation and a substantial payment for the aged debt.
  • Defended local authority client in relation to a £5million dispute for additional payment. Commenced a proactive adjudication for a contractual determination which successfully defeated the £5million claim in its entirety.
  • Drafting the contractual documents for a recommissioned wind turbine utilising a FIDIC Yellow Book 1999 form of contract.
  • Assisted local authority through the procurement of a new Dry-Mixed Recyclate facility; which involved drafting the ITT, PQQ and drafting the construction documentation based on the NEC4 Engineering and Construction Contract.
  • Adjudication
  • Arbitration
  • Commercial positioning and negotiation
  • Litigation
  • Mediation


  • Principal Associate, Capital Law Limited (Apr 2023 – present)
  • Senior Associate, Capital Law Limited (May 2022 – Mar 2023)
  • Associate, Capital Law Limited (Nov 2020 – Apr 2022)
  • Solicitor, Capital Law Limited (Apr 2019 – Oct 2020)
  • Paralegal, Capital Law Limited (May 2017 – Apr 2019)
  • Dispute Resolution Consultant, Contract & Construction Consultants Limited (2014 – 2017)
  • Director, Attica Law Limited (2014 – 2016)


  • BPP University: Legal Practice Course (2018)
  • Cardiff University: Bar Professional Training Course (2014)
  • Cardiff University: Law LLB (2010 – 2013)

Memberships / Trustee Positions

  • The Law Society of England and Wales
  • Member of the Honourable Society of Gray’s Inn
  • Associate of the Chartered Institute of Arbitrators