Similar responses and planning mechanisms are used to deal with civil unrest, chemical and nuclear incidents, all relying on the civil contingencies secretariat in the Cabinet Office, which staffs the emergency planning Cobra system.
If necessary, ministers could deploy emergency martial law style powers under the Civil Contingencies Act 2004, although few think it will come close to being necessary.
No 10 planning for ‘all eventualities’ if number of coronavirus cases surge in UK
Source: Government to shut schools in event of UK coronavirus outbreak | World news | The Guardian