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Clifford Chance

Clifford Chance
Sean Marriott

Sean Marriott


Sean Marriott

Sean Marriott entered the law following a career as an Engineer, and specialises in international commercial arbitrations and investment treaty arbitrations (including under LCIA, ICC, UNCITRAL, LMAA and ICSID rules) in the energy, resources, construction and infrastructure sectors, with a focus on offshore and onshore construction and mining arbitrations.

Sean has advised principals, contractors, insurers, and vessel owners in construction and oil and gas matters in the UK, EMEA, Latin America, and Asia-Pacific. Sean's cases have involved offshore platforms including semi-submersibles, FPSOs, drillships, jack-ups, subsea pipelines and associated infrastructure, and Sean has advised clients in maritime and transportation cases in the oil and gas sector. Sean has also advised in several mining arbirtations and electrical power generation and supply cases.

  • Global oil & gas contractor in two related international arbitrations arising out of:

    • a design and construction contract for an LNG loading jetty in Western Australia (UNCITRAL Rules, Perth seat; Western Australian governing law) 
    • a consortium agreement for the construction of the same LNG loading jetty (ICC Rules, Singapore seat; Western Australian governing law)
  • Australian mining company in an ICSID arbitration against the Arab Republic of Egypt under the Australia-Egypt BIT
  • Lead contractor against subcontractor in an international arbitration concerning losses arising from delays in the construction of a first commercial production oil and gas facility in the Middle East, including issues of work sequencing and schedule management
  • Rig owner in a breach of warranty claim against offshore construction contractor for losses arising from late delivery of rig in a non-operational state, involving issues of concurrent delay, disruption, extension of time provisions and related matters
  • Power Supplier in Western Australian arbitration against an iron ore mine operator concerning supply interruptions, operations and maintenance obligations, compliance with industry technical standards, and misrepresentation in relation to network design requirements and responsibility
  • FPSO owner in a London arbitration concerning losses arising from late completion of a wellhead management computer system during construction and associated permitted delay claims
  • Insurer in a coverage dispute under English and New York law concerning a subsea pipeline buckle giving rise to physical damage and business interruption losses
  • Co-Owners and Joint Operators concerning liability for the costs of repair of damaged subsea facilities, and associated production sharing rights, including issues of unjust enrichment and the tort of conversion

News and client work

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Contact details

Career and qualifications

  • University of Sheffield (B.Eng.) 2000
  • Admitted as a solicitor in England & Wales 2010
  • Associate Clyde & Co (London) 2010
  • Joined Clifford Chance 2016

Professional bodies

  • Member of the Society of Construction Law Australia and of the Chartered Institute of Arbitrators.