Lockdown

The Earth went into a lockdown at some point in the year 2020, due to COVID-19. (PROSE: The Invasion of London, Flower Power, The Edge of Glory)

Lucy Wilson was stuck at home with her family during the lockdown. She found the isolation difficult. (PROSE: Copy/Paste, Sweet Revenge)

Also that year, Gloucester was briefly placed under lockdown by the Judoon, using a zonal enforcement field, as they searched for the Doctor. (TV: Fugitive the Judoon)

Other types of lockdown
The Celestial Omnibus had a "lockdown" feature for emergencies, which would seal the bus up indefinitely. (AUDIO: The Iris Wildthyme Appreciation Society)

Behind the scenes
The lockdown mentioned in Sweet Revenge was a timely reference to the real life lockdown that took place due to the.