question: Background The COVID-19 pandemic imposed multiple restrictions on healthcare services. Objective To investigate the impact of the pandemic on Allergy & Immunology (A&I) services in the UK. Methods National survey of all A&I services registered with the Royal College of Physicians and/or British Society for Allergy and Clinical Immunology. The survey covered staffing, facilities, personal protective equipment, appointments & patient review, investigations, treatments and research activity. Weeks commencing 03 Feb’20 (pre-COVID), 06 April’20 and 08’May’20 were used as reference points for the dataset. Results 99 services participated. There was a reduction in nursing, medical, administrative and allied health professional staff during pandemic; 86% and 92% of A&I services continued to accept non-urgent and urgent referrals respectively during the pandemic. There were changes in immunoglobulin (Ig) dose and infusion regimen in 67% and 14% of adult and pediatric services respectively; 30% discontinued immunoglobulin replacement in some patients. There was a significant (all variables, p≤0.0001) reduction in the following: face-to-face consultations (increase in telephone consultations), initiation of venom immunotherapy, sublingual and subcutaneous injection immunotherapy, anesthetic allergy testing and hospital procedures (food challenges, immunoglobulin and omalizumab, administration); and a significant increase (p≤0.0001) in home therapy for immunoglobulin and omalizumab. Adverse clinical outcomes were reported, but none were serious. Conclusion The pandemic had significant impact on A&I services leading to multiple unplanned pragmatic amendments in service delivery. There is an urgent need for prospective audits and strategic planning in the medium and long term to achieve equitable, safe and standardised healthcare.