Amongst measures being mulled by the government is this measure copied from Guardian
Code:
M25 road block
To stop a major surge in London spreading across the country, ministers could advise no travel for Londoners past the M25, effectively isolating the capital city. In practice this would be almost impossible to police and highly disruptive for the 9 million people living in the city. It would have to take the form of guidance rather than an edict and could lead to anger against any Londoners found elsewhere in the country. Jenrick also dismissed reports about this measure being on the table as speculation.
I really do hope this hair brain plan isn't executed