Performance of antigen lateral flow devices in the UK during the alpha, delta, and omicron waves of the SARS-CoV-2 pandemic: a diagnostic and observational study by Eyre, DW, Futschik, M, Tunkel, S, Wei, J, Cole-Hamilton, J, Saquib, R, Germanacos, N, Dodgson, AR, Klapper, PE, Sudhanva, M, Kenny, C, Marks, P, Blandford, E, Hopkins, S, Peto, TEA, Fowler, T