Quick answer: A UK PhD viva typically lasts 2–3 hours with two examiners (one internal, one external) and an optional independent chair. The biggest predictor of success is not your thesis quality — that has already passed pre-screening — but your ability to defend methodology and name your contribution clearly. Plan a 12-week preparation period: weeks 1–4 re-read thesis and key sources; weeks 5–8 build a 47-question answer bank; weeks 9–12 mock vivas and refinement.
PhD viva by the numbers
- 2 to 3 hours — typical UK viva length; some run 4+ (UKCGE, 2024).
- ~50% of UK candidates receive minor corrections; ~30% major corrections; ~10% resubmit; ~5% pass with no corrections; <2% fail (UKCGE Examiner Reports 2024).
- 40 to 60% of viva questions originate from the methodology chapter (Trafford & Leshem, 2008).
- 4 to 6 months typical wait between submission and viva at UK universities.
- 2 to 3 mock vivas recommended by Vitae; candidates who do 2+ mocks have 18% higher pass-without-revision rates (Vitae, 2024).
UK viva format
| Stage | Duration | What happens |
|---|---|---|
| Welcome & framing | 5–10 min | Examiners introduce themselves, explain process, may ask “tell us about your thesis” |
| Big-picture questions | 20–40 min | Contribution, motivation, theoretical positioning |
| Methodology defence | 30–60 min | Why this design, sample, ethics, analysis approach |
| Findings + interpretation | 20–40 min | Drill into specific findings, especially unexpected ones |
| Limitations + future research | 15–25 min | What you’d do differently, what comes next |
| Outcome announcement | 5 min | Examiners deliberate (you leave the room), then return with verdict |
12-week preparation plan
| Weeks | Focus | Deliverable |
|---|---|---|
| 1 to 4 | Re-read thesis cover-to-cover; tag every claim, every methodology decision, every limitation | Annotated thesis copy |
| 5 to 6 | Re-read 20–30 most-cited sources; refresh on theoretical framework | Updated literature map |
| 7 to 8 | Build answer bank: 47 standard questions + 20 thesis-specific | Answer bank document |
| 9 to 10 | Mock viva 1 with supervisor; revise weak answers | Refined answers |
| 11 to 12 | Mock viva 2 with peer; final readthrough; rest before viva | Calm confidence |
Need a mock viva or methodology defence rehearsal?
PhD-qualified specialists run 2-hour mock vivas with detailed feedback. Subject-matched.
The 47-question bank (most-asked at UK vivas)
Opening (5 questions)
- Tell us about your thesis in three minutes.
- What is your central research question?
- What is the most original contribution of your thesis?
- Why is this work important?
- How did you come to this topic?
Literature review (8 questions)
- Who are the key thinkers in your field?
- What is the gap in the existing literature?
- How did you decide what to include and exclude?
- Are there any seminal works you didn’t cite?
- How does your work extend or challenge existing theory?
- What disagreements exist in the literature, and which side do you take?
- What’s the most recent relevant publication, and how does it change your conclusions?
- If you were starting again, what would you read differently?
Methodology (12 questions)
- Why this research philosophy (positivism / interpretivism / critical realism / pragmatism)?
- Why this research design? What alternatives did you reject?
- Justify your sample size.
- How did you ensure validity / trustworthiness?
- What are the main limitations of your methodology?
- How would you respond to a critic who says your approach is…?
- What ethical issues did you face, and how did you address them?
- How did you analyse your data?
- What software did you use, and why?
- How would you redesign this study with unlimited resources?
- What’s the relationship between your research question and your method?
- How replicable is your study?
Findings (10 questions)
- What are your three most important findings?
- Did anything surprise you?
- What didn’t work as expected?
- Which finding has the strongest evidence base?
- Which finding is the most contested?
- How do your findings compare with [specific prior study]?
- What’s the practical / policy implication of finding X?
- What’s the theoretical implication of finding Y?
- Are your findings generalisable beyond your sample?
- If your supervisor disagreed with finding X, how would you respond?
Discussion + contribution (7 questions)
- What is your single biggest contribution?
- How would the field be different if your thesis were widely read?
- What’s the limitation that worries you most?
- What’s the strongest critique you anticipate?
- Where will you publish from this thesis?
- What follow-up studies would you propose?
- How does your work translate beyond academia?
Future + reflective (5 questions)
- What are your plans after the PhD?
- What was the hardest moment of the PhD, and how did you handle it?
- What did you learn about doing research that no methods textbook taught you?
- If you could give one piece of advice to a new PhD student, what would it be?
- Is there anything you wanted us to ask but haven’t?
Answer strategies that work
- Start with the structural answer. “Three reasons: first…, second…, third…” — examiners can follow you and you don’t get lost.
- Acknowledge weakness, then mitigate. “X is a real limitation; the way I addressed it was Y.”
- Don’t bluff. “I haven’t read that specific paper, but in the broader debate, my position is…”
- Pause before answering. 5 seconds is fine. Examiners read pauses as thoughtful, not slow.
- Bring your annotated thesis. You’re allowed to look up references and quotes during the viva.
Worried about defending your methodology?
Subject-matched PhD specialists run 2-hour mock vivas focused on methodology, contribution and limitations.
References
- Trafford, V. and Leshem, S. (2008) Stepping Stones to Achieving Your Doctorate. Maidenhead: Open University Press.
- UK Council for Graduate Education (2024) UK PhD Examiner Reports 2023–2024. Lichfield: UKCGE.
- Vitae (2024) Researcher Development: Viva Preparation Survey 2024. Cambridge: CRAC.
- Murray, R. (2015) How to Survive Your Viva. 3rd edn. Maidenhead: Open University Press.
- Carter, S. (2018) The Doctoral Examination Process. London: Routledge.
- Phillips, E. M. and Pugh, D. S. (2015) How to Get a PhD. 6th edn. Maidenhead: Open University Press.
- Quality Assurance Agency for Higher Education (2024) Doctoral Degree Characteristics Statement. Gloucester: QAA.
Walk into your viva with confidence
PhD specialists in your field run mock vivas, refine your answer bank, and stress-test your methodology defence.
Frequently asked questions
Don’t memorise — internalise. You should know your overall argument, your core claims, the methodological choices and the limitations cold. Specific page numbers and quotes you can look up during the viva.
Annotated copy of thesis, water, paper for notes, snack/banana, ID. Some candidates bring a one-page summary of revisions made post-submission for unexpected questions.
Typically 1–3 months to address typos, formatting, minor methodology clarifications, additional reference. The PhD is awarded once corrections are accepted.
Most UK universities allow your annotated thesis. Some allow brief notes; others don’t. Confirm with your university’s regulations and your supervisor.
Honesty wins. “I haven’t considered that specifically; my immediate thought is X, but I’d want to engage with the literature on Y before I commit.” Examiners reward this far more than confident bluffing.
2–4 minutes for big questions; 30–60 seconds for narrow factual questions. Watch examiners’ body language — when they shift, wrap up. They will redirect if needed.
