
Francis Taylor Building
Barristers

Mark O\'Brien O\'Reilly
- Phone02073538415
- Email[email protected]
Position
Mark is a leading barrister with a growing reputation for experience and skill beyond his call. He is ranked as one of the top junior planning barristers in the country by Planning Magazine’s Planning Law Survey 2024 (and also holds a ranking as one of the top ten planning barristers under the age of 35 with Planning Magazine noting he was the highest new entrant on that list and his particular injunction expertise). The High Court has described his submissions as “concise and well-structured”. Clients have praised him as “commercial” and “user friendly”.
Mark regularly appears at planning inquiries concerning a broad range of developments, with a particular expertise in residential schemes, tall buildings and renewable energy projects. He has recently successfully promoted a 49.9MW solar farm scheme at inquiry and acted in the Court of Appeal on behalf of the Interested Party defending the grant of planning permission for hydrocarbon exploration and appraisal within an AONB. Other recent significant cases include successfully defending the DCO for Manston Airport in both the High Court and the Court of Appeal, numerous successful applications in the High Court for planning injunctions and representing the Royal Borough of Greenwich in the Mast Quay Enforcement Notice appeal having advised the Council throughout the enforcement investigation (a 204 unit residential development consisting of two tall buildings beside the River Thames).
Mark has a strong and busy practice across all of Chambers’ practice areas, with a particular expertise in planning, infrastructure and compulsory purchase/compensation work. Mark has a strong reputation as an advocate and, unusually for his year of call, regularly appears in the High Court, including as sole counsel and against leading KCs. His advocacy experience, including cross-examining in the Old Bailey, means he is generally instructed against more senior counsel, including KCs. He appears before a broad range of courts, tribunals and planning inquiries. He is also regularly instructed as junior counsel to other members of Chambers, including leading silks. He has a broad range of clients ranging from developers, renewable energy companies and landowners to local residents. He has extensive experience of acting for, and advising, central government and local government (and has acted for many London boroughs).
Mark is in demand for his planning expertise, and regularly acts for both appellants and local planning authorities in planning inquiries. He is also noted for his strong experience of injunctions, including section 187B injunctions, and is regularly called upon, often urgently, to advise upon and obtain High Court injunctions (and has acted in many of the recent reported cases concerning section 187B injunctions).
During his pupillage, Mark was awarded the Reid Scholarship by Gray's Inn, a Senior Scholarship for Pupillage, which is the Inn's most prestigious scholarship and awarded to a pupil barrister of exceptional merit. He is a First Class Honours graduate of University College Dublin (BCL Law with History) and the University of Cambridge (LLM). Mark was called to the Bar of England and Wales in 2021 and the Bar of Ireland in July 2023.
Mark welcomes instructions across all of Chambers' practice areas, with a particular interest in planning, public and compulsory purchase/compensation as well as licensing and environmental law.
Away from his busy practice, Mark owns and breeds racehorses. He is well placed, therefore, to advise racing yards, stud farms and racecourses as well as a broad range of equestrian facilities on the planning issues they face. He also enjoys travelling and volunteering.