NHS staff are having to leave the frontline to self-isolate because they or family members cannot book a test. NHS Providers says that if the shortage is not addressed soon it will wreak havoc for hospitals as virus cases continue to escalate. In another humiliating blow to the testing system, head teachers have warned that schools - which were closed for months because of the pandemic - will 'grind to a halt' if teachers can't get tested quickly. Health officials have blamed the crisis - which experts fear will rumble on for weeks - on a staffing shortage. Desperate bosses have now admitted they may have to hire students to plug gaps in the rota in the face of sky-high demand. Other experts have blamed the problems on a 'critical pinch point' in labs that process the tests due to a sudden spike in demand. But government sources say the actual cause of the crisis is the 'closely guarded secret in Whitehall'. It came as an investigation by the LBC radio station yesterday found there were no test bookings available at any of the country's ten coronavirus hotspots including Bolton, Salford, Bradford and Manchester. But Priti Patel denied that tests were unavailable in the country's worst-hit areas. The Home Secretary told BBC Breakfast today that she has seen with her own eyes that swabs are available in towns hit by local lockdown rules.