About Mark

Mark is a partner in our litigation & dispute resolution team. Mark works with major financial institutions, State bodies, owner-managed businesses, corporates and individuals. For over two decades Mark has practiced exclusively as a litigator throughout the Irish Courts system, with a particular focus on commercial disputes and proceedings in the Commercial Court.

Mark has wide-ranging expertise in administrative law, arbitration, banking, bankruptcy, contractual disputes, company law, construction, constitutional law, debt recovery, employment, enforcement, equality, insolvency, judicial review, landlord and tenant law, negligence, planning, probate, professional negligence and other tort actions.

Recent experience

  • Kenmare Property Finance Limited in successfully opposing an application for injunction to prevent execution of possession order, previously obtained by Beauchamps in the High Court and upheld in the Supreme Court, in respect of boutique hotel premises and securing High Court order striking out the plaintiff’s proceedings as an abuse of process
  • Allied Irish Banks plc in ongoing defence of High Court proceedings brought by guarantor who seeks to avoid €1.5 million personal guarantee
  • NAMA in securing a €25 million High Court Judgment against a debtor and obtaining Judicial Review from the Supreme Court quashing attempts by the debtor to bring private criminal prosecutions against individual staff members of the former IBRC
  • A significant property holding and development company in successfully opposing an application for mandatory injunction, the effect of which would have been to require our clients to enter into a disputed multi million euro commercial agreement which our clients previously terminated
  • Allied Irish Banks plc in the successful defence of proceedings brought by the members of a family trust who claimed to be entitled to the beneficial interest in a multi million euro property portfolio in the UK and Ireland over which the client bank held security granted by the legal owners
  • A receiver in securing High Court Injunctions granting possession of valuable commercial premises in favour of the Receiver despite objections by a mortgagor and its tenant and the latter’s attempt to rely on a lease granted without mortgagee consent



Very personable and at the same time thorough; he is focused on the outcome rather than just the process.
Chambers & Partners 2018
Mark Heslin has "a good grasp on the details"
Chambers & Partners 2017
Very intricate knowledge of the entire case, with a full understanding of every fine detail at his fingertips.
Chambers & Partners 2016
Highly responsive and very analytical.
Chambers & Partners 2015
Built a strong practice in commercial litigation.
Chambers & Partners 2014