The largest pandemic simulation in UK history — a Tier 1 national emergency exercise involving every government department, all devolved governments, and hundreds of local resilience forums. Simulated a novel enterovirus (EV-D68) that disproportionately affected children, causing respiratory failure, brain swelling, and paralysis.
View Evidence Cards Back to HubPrimary evidence from Exercise Pegasus — the UK’s post-COVID pandemic preparedness exercise and the largest ever conducted in the country.
Exercise Pegasus was designated a Tier 1 national emergency exercise — the highest possible classification. It involved every government department, all devolved administrations (Scotland, Wales, Northern Ireland), local resilience forums, NHS trusts, businesses, and academic institutions. It surpassed Exercise Cygnus (2016) in both scale and scope.
The simulated pathogen was a novel enterovirus — EV-D68 — originating from a fictional island. In the scenario it caused respiratory failure, brain swelling, and in rare cases paralysis in infants, children and teenagers. This mirrored the “Catastrophic Contagion” scenario (2022) which also focused on pathogens affecting young people.
Pegasus was the first national pandemic simulation in nearly a decade — conducted after the UK COVID-19 Public Inquiry exposed that Exercise Cygnus findings had been ignored for four years. The exercise was explicitly designed to incorporate lessons from COVID-19 and avoid repeating the failures documented by the Inquiry.
Reports emerged that schools across the UK were locked down as part of Exercise Pegasus — simulating school closures under a pandemic scenario. Ministers were reported to have admitted the country “still isn’t ready” for the next pandemic. The secrecy of the exercise drew comparisons to the classified Exercise Cygnus.
Unlike previous exercises that focused on a single moment in time, Pegasus tested all three pandemic phases: Emergence (initial detection and reporting), Containment (isolation, contact tracing, border measures), and Mitigation (mass healthcare response, social measures, economic protection). This comprehensive approach was a direct response to criticism that Exercise Cygnus only tested “peak pandemic.”
Pegasus is the latest in a series of UK pandemic exercises stretching back two decades: Exercise Winter Willow (2007, pandemic flu), Exercise Cygnus (2016, H2N2), Exercise Alice (2016, MERS). The pattern is consistent: exercises reveal preparedness gaps, reports are classified or ignored, and the next real crisis validates the warnings. The question is whether Pegasus will break this cycle.
A three-month exercise spanning September to November 2025, testing the UK’s response from initial detection to nationwide mitigation.
A novel enterovirus (EV-D68) is detected on a fictional island. Early surveillance systems are tested. International health regulations trigger reporting to WHO. UK public health agencies begin risk assessment.
Imported cases appear in the UK. Contact tracing systems are activated. Schools begin implementing emergency protocols. The virus’s particular impact on children creates political pressure for school closures. Hospital paediatric wards come under strain.
Containment fails. The exercise enters mitigation mode: mass healthcare surge, social distancing measures, school closures, economic protection packages. All government departments and devolved administrations coordinate their response plans. Debrief and lessons identified process begins.
Exercise Pegasus involved an unprecedented breadth of UK government and public service bodies.
While the full after-action report has not yet been publicly released, early indications suggest Pegasus confirmed several ongoing vulnerabilities.
The scenario tested the UK’s ability to respond to a pathogen disproportionately affecting children — a scenario not covered by previous exercises (Cygnus, Alice). Paediatric ICU capacity and vaccine prioritisation for children were stress-tested.
Pegasus tested the political and operational decision-making around school closures — one of the most contested policies during COVID-19. The exercise simulated the tension between public health advice and educational impact.
After the UK’s £37 billion Test and Trace programme during COVID-19 was widely criticised, Pegasus tested whether scalable tracing infrastructure was now in place. Early reports suggest significant gaps remain.
COVID-19 exposed significant tensions between the UK Government and devolved administrations over lockdown timing and messaging. Pegasus tested whether four-nation coordination frameworks had been improved since 2020.
The UK COVID-19 Inquiry issued numerous recommendations for pandemic preparedness. Pegasus served as a real-world test of whether those recommendations had been implemented — or whether the Cygnus → ignore → fail pattern was continuing.
Tested public communication strategies for a pandemic affecting children — a scenario guaranteed to produce heightened public anxiety and potential for misinformation. Social media response protocols and counter-misinformation measures were evaluated.
Exercise Pegasus sits at the end of a two-decade chain of UK pandemic exercises — each one revealing gaps, each one largely ignored until the next crisis.
| Exercise | Date | Pathogen | Classification | Key Finding |
|---|---|---|---|---|
| Winter Willow | Feb 2007 | Pandemic Influenza | Published Aug 2007 | Mass burial planning needed; local government overwhelmed |
| Exercise Alice | Feb 2016 | MERS-CoV | Classified until Oct 2021 | PPE stockpile warnings; contact tracing absent |
| Exercise Cygnus | Oct 2016 | H2N2 “Swan Flu” | Classified until Oct 2020 | NHS would collapse; 22 recommendations ignored |
| COVID-19 (Reality) | 2020–2023 | SARS-CoV-2 | — | All exercise warnings validated; £37B Test & Trace |
| Exercise Pegasus | Sep–Nov 2025 | EV-D68 (Enterovirus) | Report pending | Largest ever; children-focused pathogen; school closures tested |
Will Exercise Pegasus break the cycle? The UK COVID-19 Inquiry has created unprecedented public pressure for implementation. But the same pressure existed after Cygnus was declassified in 2020 — and the Inquiry found that Cygnus’s 22 recommendations had been largely ignored. The test is not the exercise. The test is what happens next.
Written Statement HCWS1015 — Pandemic Preparedness: Exercise Pegasus (Nov 4, 2025)
Pandemic Preparedness & Exercise Pegasus — Long read guidance (Jul 16, 2025)
The Telegraph — Schools locked down again in secret pandemic drills (Nov 25, 2025)
UK COVID-19 Public Inquiry — Context for why Pegasus was commissioned