A Chinese scientist who is the one of the world's leading experts on coronaviruses was 'muzzled' after unravelling the genetic composition of the new disease, which is crucial for developing diagnostic tests and vaccines.

The revelation will fuel fresh concerns over China's cover-up of the pandemic after it erupted in the city of Wuhan. Critics argue that Communist Party chiefs frustrated efforts to contain the outbreak before it exploded around the world.

At the centre of the new claims is Shi Zhengli, known as China's 'Bat Woman' after years spent on difficult virus-hunting expeditions in dank caves that have led to a series of important scientific discoveries.

The virologist was called back to her highsecurity laboratory in Wuhan at the end of last year after a mysterious new respiratory condition in the city was identified as a novel coronavirus – and within three days she completed its gene sequencing.