A technical glitch caused nearly 16,000 Covid-19 cases to go unreported in England due to an old file format used by Public Health England (PHE) to bring together logs produced by commercial firms. Each Excel template could handle only about 65,000 rows of data rather than the one million-plus rows that Excel is actually capable of, limiting each template to about 1,400 cases. When that total was reached, further cases were simply left off. The health secretary has said that this issue 'should never have happened'.