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Her Majesty Queen Elizabeth II 1926 - 2022

Portrait of David O'Brien


David is a partner in the commercial dispute resolution team, specialising in high value, complex commercial and financial disputes, including acting for banks and other financial institutions.

He also leads the firm’s group actions team, often representing large numbers of claimants in high value, multi-party actions against solicitors and other advisers. He is considered a leading claimant lawyer in group actions arising from failed investment schemes. David is known for his technical and strategic legal nous and his ability to develop practical solutions to achieve results for clients.

In the latest edition of The Legal 500  he has been described as 'phenomenally clever, hard working and insightful' and 'one of the brightest and most astute litigators in the market' with 'an encyclopedic grasp of relevant law and procedure' and as providing a 'magic circle service'.  He is also noted by counsel as being 'one of the best solicitors I have ever worked with' and 'entirely committed to serving his clients'.

Recent work highlights

  • Defending a claim for damages arising from the alleged repudiation of an agreement for the sale of financial instruments.
  • Acting for 170 claimants in a professional negligence action relating to the purchases of leasehold interests in the Key Homes development schemes.
  • Acting for 102 claimants in Various Claimants v Giambrone and Law (a firm) and Others, a complex professional negligence and breach of trust claim relating to off-plan property purchases in Italy.
  • Defending proceedings for the alleged breach of an international distribution agreement.
  • Acting for the claimant in Marksans Pharma Limited v Peter Beck and Partner GmbH in its successful claim over the performance of a contract for the sale of $27 million worth of convertible bonds and defending a counterclaim for damages.

Penningtons Manches Cooper LLP

Penningtons Manches Cooper LLP is a limited liability partnership registered in England and Wales with registered number OC311575 and is authorised and regulated by the Solicitors Regulation Authority under number 419867.

Penningtons Manches Cooper LLP