Panorama goes undercover inside a lab analysing thousands of Covid-19 tests per day. Secretly filmed footage reveals a failing service with shoddy practices, where staff complain they are under pressure to meet targets despite the lab often running well below capacity.

The programme discovers there have been three outbreaks of coronavirus among staff and that social distancing is poorly maintained. Test samples sometimes arrive poorly packaged and labelled, with equipment frequently malfunctioning, leading to contamination of results. The programme also discovers that tests, including some intended to find new variants of coronavirus, have been wrongly discarded or lost.