David was called to the Bar of England and Wales in 1983 and to the Bar of Northern Ireland in 2009. He is a Recorder, Deputy High Court Judge and Judge of the Upper Tribunal (Immigration and Asylum Chamber) and a qualified mediator. He has been called ad hoc in Hong Kong. He specialises in land use planning, environmental, valuation, compulsory purchase, public law and property and acts for a wide spectrum of individuals, action groups, commercial bodies, government and non-governmental organisations. Comments from Chambers & Partners and the Legal 500 include:
"He is first-rate when it comes to inquiry work and High Court and Court of Appeal litigation. He is a very good advocate who is very articulate and has a very incisive mind. He can cut through legislation and provide a sensible answer." 
"A true environmental law specialist, who has a varied, top end practice in this area. He is trusted by large corporate clients and the government to lead on high stakes judicial reviews and litigation. Waste cases prove a particular specialism for him… He is a giant of the Environmental Bar." "He's good to use when you have a heavyweight issue and need to get something resolved quickly." 
"Has a nice court style and produces clear submissions with humour mixed in. The court listens to him and he can turn a case around." 
"He's incredibly bright and there's no one better than him in understanding complex points". "He's incredibly clever and incredibly hard-working. We call him two brains because he can do two things at once." 
"Said to 'ooze brain power,' David Elvin QC is feared by his opponents in any contentious planning matter. A real client favourite, he is 'great in front of judges' and a man who gets results. Also a member of the Northern Ireland Bar and someone with experience of the European courts, he is a well-travelled barrister whose excellent reputation is well known far and wide." 
Notable and recent activity relating to work outside England and Wales includes:
- CLP Power Hong Kong Ltd v Commissioner of Rating & Valuation Judgment 2.2.16 (CACV 202/2015) recent successful appeal to the Hong Kong Court of Appeal concerning the liability to rating of certain machinery forming part of power station infrastructure.
- Advisory work in Hong Kong on planning, noise nuisance and land registration. Advisory work in the Isle of Man on planning, human rights and rights of way.
- Re Newry Chamber of Commerce and Trade's Application for Judicial Review  NIQB 65 – concerning a Northern Ireland judicial review on planning, habitats and environmental issues.
- Re Alternative A5 Alliance's Application for Judicial Review  N.I. 96 – judicial review concerning the habitats implications of a new road scheme.
- Re National Trust's Application for Judicial Review  NIQB 60 – challenge to a decision said to affect the Giants’ Causeway World Heritage Site.
- Quinto v Santiago Castillo Ltd  UKPC 15 – appeal from Belize concerning alleged fraud in land registration and rectification.
- Commission of the European Communities v UK (C-508/03)  E.C.R. I-3969 and R (Barker) v Bromley LBC (C-290/03)  E.C.R. I-3949 – environmental assessment of reserved matters in planning applications.
- R (Wells) v Secretary of State  E.C.R. I-723 – environmental assessment, direct effect and procedural autonomy.
- Re Foster’s Application for Judicial Review  N.I. 248 – application of the ECHR to the Northern Ireland planning system.
- Chapman v UK (2001) 33 E.H.R.R. 18 – Strasbourg case on gipsies, article 8 and the right to a home.
Currently working on the CLP Power HK rating issues in Hong Kong and in several judicial reviews in Northern Ireland – including the dispute over dredging sand from Lough Neagh and habitats issues and the challenge to the Northern Ireland Single Planning Policy Statement.