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Mariusz Rumun

Call 2019

Professional Liability

Mariusz been involved in professional liability claims across a variety of different professions including auctioneers, insurance brokers, managing agents, solicitors, architects and other construction professionals.

Examples of Mariusz’s work include:


  • Defending solicitors in a £100,000+ claim concerning the payment of conveyancing money directly to the beneficiary under a discretionary trust, rather than into the trust account.
  • Defending solicitors in a claim for loss of a chance, concerning allegations of negligence against the defendant firm regarding the choice of defendants and causes of action.
  • Defending solicitors against allegations of breach of undertakings, negligence, breach of fiduciary duty and breach of trust in connection with their involvement in the proposed purchase of a commercial development.
  • Advising and drafting a claim against solicitors with regards to their involvement in a fraudulently obtained bridging loan secured by a charge on the claimant’s property (as a pupil).
  • Advising solicitors on liability following the sale of a property under a fraudulently executed power of attorney, raising issues of breach of duty, breach of trust, breach of undertaking, and breach of warranty of authority (as a pupil).

Construction Professionals

  • The Grenfell Tower Litigation: Mariusz acts, as part of a team led by Andrew Rigney KC, in respect of civil claims arising out of the Grenfell Tower Fire.
  • Acting for an architect in an adjudication concerning the design and contract administration of concrete works in the development of a new tram terminal.
  • Advising consulting engineers as to the contractual and tortious duties owed by them in respect of issues of defective design and delay in connection with a major development (as a pupil).

Insurance Brokers

  • Defending a claim against an insurance broker alleging a failure to effect insurance to cover loss of rent and legal expenses in connection with a commercial property portfolio.


  • Defending letting agents in a High Court claim following a failed attempt by a landlord to obtain possession of a property by way of a notice under section 21 of the Housing Act 1998.
  • Defending a claim brought against a real estate auctioneer concerning the information contained in the auction catalogue.
  • Defending a claim arising out of the answers provided by the defendant to enquiries contained in a CON29 Drainage and Water Report.

Selected Cases

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  • Lord Denning Scholarship, Lincoln’s Inn (2018)
  • BPTC Advocacy Scholarship, BPP University (2018)



  • MA in Law, University of Cambridge, Downing College
  • LLM Commercial Law (Distinction), London School of Economics and Political Science
  • BPTC, BPP Law School


  • PNBA

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