It is a rare glimpse inside the Chinese laboratory at the centre of mounting inter-national suspicion about the Covid-19 pandemic – and will do nothing to dispel fears that it was caused by a catastrophic leak which has been covered up by Beijing.

Pictures from inside Wuhan’s secretive Institute of Virology show a broken seal on the door of one of the refrigerators used to hold 1,500 different strains of virus – including the bat coronavirus which has jumped to humans with such devastating effect.

The pictures, first released by the state-owned China Daily newspaper in 2018, were published on Twitter last month, before being deleted. One comment attached read: ‘I have seen better seals on my refrigerator in my kitchen.’

The Mail on Sunday revealed a fortnight ago that Ministers now fear that the pandemic could have started as the result of a leak.