Business Interruption cover is intended to provide cover following physical loss or damage to your premises, caused by an insured peril e.g. storm, fire, flood and theft.
There has been a lot of poor reporting by the major news outlets suggesting that if the Government impose a shutdown then insurance will kick in. Unfortunately, they have failed to report the response from the Association of British Insurers, pointing out that the overwhelming majority of businesses will not have cover in place for the current situation.
https://www.abi.org.uk/news/news-articles/2020/03/statement-on-business-insurance-and-coronavirus/