Derek O'Sullivan QC

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+44 (0)20 7832 1111

“One of his real fortes is cross-examination – he’s like a dog with a bone”.
Chambers and Partners 2014

Derek O’Sullivan QC’s practice concentrates on personal injury and he has significant experience in: catastrophic injury claims, employer’s liability claims, occupier’s liability claims, fatal accident claims and road traffic accidents. Derek is also regularly instructed in health and safety matters as well as property damage claims.

Derek was named ‘Personal Injury & Clinical Negligence Junior of the Year‘ at the Chambers Bar Awards 2012.

Personal Injury

“Great fun to work with, he shows excellent attention to detail and is a very bold negotiator and tactician.” Chambers and Partners 2015

Derek O’Sullivan has a very extensive personal injury practice and is an Assistant Editor of Kemp News.

Employer’s Liability Claims

Derek has acted in a very considerable number of EL claims. His experience includes cases involving the following:-

Questions relating to the status of a claimant (i.e. whether or not a claimant is owed a duty as an “employee”)

  • The Workplace (Health Safety and Welfare) Regulations 1992
  • The Manual Handling Operations Regulations 1992
  • The Health and Safety (Display Screen Equipment) Regulations 1992
  • The Personal Protective Equipment Regulations 1992/1998
  • The Control of Substances Hazardous to Health Regulations 1988/1999/2002
  • The Construction (Health Safety & Welfare) Provisions 1996
  • The Provision and Use of Work Equipment Regulations 1992
  • The Management of Health and Safety at Work Regulations 1999
  • The Electricity at Work Regulations 1999
  • The Work at Height Regulations 2005
  • Lifting Operations and Lifting Equipment Regulations 1998
  • Construction (Design and Management) Regulations 2007

Occupational Illness Claims

  • Stress at Work
  • Bullying/harassment
  • Deafness
  • Asthma
  • Pudendal Nerve Entrapment Syndrome (an unusual physical condition arising in a workstation/display screen case)
  • Dysphonia
  • Asbestos related illnesses/Mesothelioma

Rail Claims

For many years Derek has acted for rail companies in relation to claims by passengers, trespassers and claims by injured employees. He is familiar with the issues in rail claims (including CAHA) and has a good knowledge of the relevant Master Rule books and Railway Standards (these being highly relevant in the case of Collins-Williamson (see above) which concerned (in part) an attack by the claimant on the overall safety of train despatch systems on the rail network).

Carbon Monoxide poisoning claims

Derek has considerable experience in defending claims arising from carbon monoxide poisoning; he has a decent level of technical knowledge in relation to the engineering issues that generally arise in these cases as well as arguments arising from, inter alia, the Gas Safety (Installation and Use) Regulations 1998. He was Counsel for British Gas Services Ltd in the case of Sestilli v (1) British Gas Services Ltd (2) Paul White (2010); this was a multi-million pound personal injury claim arising from alleged CO poisoning.

Employer’s Liability Claims involving accidents at sea or onboard ships

Derek has wide experiences in this niche area and has experience of cases involving the following:-

  • The Shipbuilding and Ship-Repairing Regulations 1960
  • The Docks Regulations  1988
  • The Merchant Shipping and Fishing Vessels (Health Safety & Welfare) Regulations 1997
  • Liability generally where UK regulations do not apply

Aviation Claims

Derek has a growing practice being instructed in relation to personal injury claims arising from accidents aboard aircraft (both fixed wing and helicopters); Derek has dealt with Montreal convention cases together with non-Convention cases where liability for the accident is in dispute.

Derek is also currently instructed by London City Airport in relation to an industrial illness claim (by an airside worker) involving alleged breaches of the Control of Substances Hazardous to Health Regulations.

Conflicts of Laws/Accidents abroad

Personal injury claims frequently accidents abroad and so conflicts of laws issues (including Rome II issues) are frequent in Derek’s practice; Derek has lectured on this topic.

Occupier’s Liability Claims

Derek has acted in a very considerable number of occupier’s liability claims with the cases dealt with including:-

  • Liability of the occupiers of woodlands, nature reserves and holiday parks
  • Liability of domestic householders in relation to both the 1957 and 1984 Acts
  • Liability of the occupiers of commercial premises (both to visitors and persons attending in the course of their employment)

Road Traffic Accidents

Derek has conducted many cases arising from road traffic accidents and it not practicable to give any particular details (save to say that he has particular experience of motorcycle cases).

Animals Act 1971

Cases under the Animals Act include cases involving claimant’s being knocked down or bitten by dogs; struck by bolting horses; struck by horses kicking out; being thrown from bolting horses etc.


Derek is involved with all quantum issues generally encountered by personal injury practitioners and he is particularly well known for his involvement in catastrophic injury (either spine or ABI) cases.


Derek has a particular interest in fraud in personal injury cases. Derek has a robust view in relation to dishonesty amongst claimants and he is always keen to fight fraud cases to trial; his views are plain: if the evidence is sufficient to establish fraud then defendants should take a very firm stance.

Health and Safety Law

Derek frequently receives instructions from the employer’s liability insurers of companies and individuals who are facing health and safety prosecutions in the criminal courts.

He frequently represents companies and individual directors pleading guilty in the criminal courts and has experience of trials in both the magistrates court (e.g. R v Bestway Coventry Magistrates Court; a case under s. 3 of the Health and Safety at Work which involved a so-called “HTML defence”) and the Crown Court with a jury (e.g R v Thomas and R v County Mall Management Limited).

Previously Derek was junior Counsel in a gross negligence manslaughter case brought against a construction company (R v English Brothers, Northampton Crown Court).

Civil Liability

Product Liability

Derek has been instructed over the years by insurers in a number of product liability claims and he is currently involved in “the toxic leather Sofa” group litigation (acting for one of the many defendants).


Derek is regularly instructed to appear in Inquests and he has developed an expertise in cases involving suicides and deaths in prison custody.


Derek has considerable experience in disputes arising by reason of fraud/material non-disclosure/misrepresentation in insurance claims. He has represented insurers in a number of such cases which have proceeded to trial and which have dealt with the following:

  • Presentation of fraudulent documents/use of fraudulent devices in support of claims.
  • Presentation of fraudulent claims
  • Material non-disclosure in claims
  • Material non-disclosure/misrepresentation in insurance proposals.

He is currently involved (for insurers) in a number of such ongoing cases.

Derek has also been instructed in disputes involving policy coverage, most notably where insurers have refused to provide indemnity under non-motor policies. Cases in this area include insurers refusing to provide public liability cover to a footballer who recklessly injured a fellow player, insurers refusing to provide public liability cover to an insured who injured a friend whilst engaging in horseplay with an air-rifle and insurers refusing to provide cover in respect of a fire which had been wilfully/recklessly started.

Finally, Derek has also acted for insurers in a number of cases which have involved consideration of the various sections of the Road Traffic Act 1988 and he has been instructed in a number of cases where the Motor Insurers Bureau was a party.

Property damage claims involving utility companies/train operators

Derek has been instructed for many years in claims arising from property damage to the underground services belonging to utility companies. He has considerable experience in dealing with nuisance/negligence actions  arising from (in particular): gas explosions, underground cable strikes and interference with water mains/sewers. He has considerable experience in acting both for utility companies claiming in respect of physical damage and recoverable economic losses and also for contractors allegedly responsible for damage to underground services

Derek is also instructed by a number of train operating companies in relation to losses arising from damage to their property; in 2011 he acted for Arriva Trains Wales in a high value claim by them for financial and consequential losses arising from a level crossing accident.

Material Loss Claims

Derek has been instructed over the years by insurers in fire damage, water damage and goods lost in transit claims.

He has been involved in a large number of subsidence claims and has advised insurers in upwards of 25 of these claims over the years. In the last three years two such claims have come to trial (one involving the regrading of neighbouring land thereby causing damage to the claimant’s land and the other being whether or not movement in a building was subsidence within the meaning of an insurance policy).


He is recognised as a Leading Personal Injury junior by both Chambers and Legal 500; in Chambers 2014 Derek is a Band 1 Leading Junior.

Derek is also recognised as a Leading junior in Health and Safety and Environment law by the Legal 500.


“He is a terrific advocate and clients love his down-to-earth, no-nonsense approach.” Legal 500 2015

He has an ability to condense and communicate important issues in an exceptionally clear way.” Legal 500 2015

“A high level of pragmatism, attention to detail, and an ability to communicate issues exceptionally clearly.” Legal 500 2015

“Great fun to work with, he shows excellent attention to detail and is a very bold negotiator and tactician.” Chambers and Partners 2015

“One of his real fortes is cross-examination – he’s like a dog with a bone. He’s definitely one of the stars at the chambers, and it’s hardly a shoddy set.” “Not only is he exceptionally knowledgeable, but he also stands up in a fight. He’s extremely approachable too.” Chambers and Partners 2014

Fantastically good with clients,” the “pugnacious” Derek O’Sullivan “fights tooth and nail for his client” but never loses his “down-to-earth style.” His “realistic assessment of the chances of success” is lauded by clients.: Chambers and Partners 2012

The absolutely first rate” Derek O’Sullivan has the “ability to get right to the crux of the issues at a very early stage”. He combines a formidable legal mind with “strong social and technical skills”. Such qualities serve him well both in the Courtroom and when generally dealing with lay clients: Chambers & Partners 2011

The ‘very down-to-earth and pragmatic’ Derek O’Sullivan; Legal 500 2011 (Health and Safety)

Derek O’Sullivan is ‘excellent at cross-examination’: Legal 500 2011 (Personal Injury)

He is also applauded for his “clear and concise presentation of evidence and excellent summing-ups.”  Chambers & Partners 2010

Both thoroughness and client relationship skills are also described as being among Derek O’Sullivan’s qualities Chambers & Partners 2010

Derek O’Sullivan can be a street-fighter when you need one – he’s tough as old boots when the case dictates,” Chambers & Partners 2009

This senior performer litigates a wide variety of cases, and is a “confident, experienced advocate who cuts to the real issues very quickly and is extremely commercial.” Chambers & Partners 2009

one of the finest juniors around” Legal 500 2009


Related Cases

Personal Injury

Allen-Donald v Breedon [2011] CC

Liability of employer under the Workplace (Health, Safety and Welfare) Regulations 1992; employee injured slipping at work subsequently developed adjustment disorder / chronic pain resulting in her becoming wheelchair bound.

Orchard v Lee [2009] EWCA Civ 295

liability of two teenage school pupils to a school supervisor injured by the one of the boys in the course of a game of “tag” between the boys. Derek represented one of the children and the case against his client was dismissed at first instance; the claimant appealed against the judgment in respect of the other  child and her appeal was dismissed.

Khambhaita v Lewis (2009) QBD

liability of a driver to a pedestrian emerging onto road at a traffic light green in favour of the driver

Collins-Williamson v Silverlink Trains [2009] EWCA Civ 850, CA

liability of train company to a passenger injured by falling from station platform under a moving train

Jennings v Forestry Commission (CA) [2008] EWCA ICR 988, CA

liability of Forestry Commission to a contractor, including consideration of the employment status of the contractor and the Provision and Use of Work Equipment Regulations 1998

Lough v IDS [2008] EWCA Civ 1009, CA

liability of occupier of domestic premises to employee of an independent contractor carrying out work on the premises

Mills-Davies v Royal Society for the Protection of Birds (QBD) 2004

liability of occupier of a bird sanctuary to a visitor seriously injured when falling onto a small tree stump on a path (created by works carried out by occupier to clear a path in the sanctuary)

MacLellan v Forestry Commission (QBD) 2004

liability of occupier (of a forest adjacent to the River Wye) to a visitor seriously injured when hit by a falling tree

Grant v Dick [2003] EWHC 441, QBD

liability of driver to a pedestrian running out onto a dual carriageway

Barry v Wynn [2001] EWCA Civ 710, CA

liability of driver overtaking a stationary bus causing injury to a pedestrian

Costs & Litigation Funding

Onay v Brown 10 June 2009 (2009) EWCA Civ 775

costs and Part 36 issues arising from acceptance of an offer where primary liability had been admitted in a road traffic case

Accidents at Sea

Davis v Stena Line Ltd (QBD) [2005] 2 Lloyds Rep 13

Extent of commercial ferry operators duty and causation issues in attempted rescue in adverse weather conditions.

Aviation Accidents

Day v (1) Tasker (2) Multiflight Ltd (3) Kennett [2009] QBD

Leeds District Registry: liability and quantum issues arising from the crash of Schweizer 269C helicopter G-TASS in the Lake District on 10 May 2004


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Derek's Practice Areas

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