One of the inspiring things about Brexit is the way its boosters constantly harken back to simpler times in the country’s history, lexically and otherwise. So, it was recently bruited by Jacob Rees- Mogg that if during a transition period we must obey European rules while no longer helping to write them, Britain will become a “vassal state”.

In feudal times, a “vassal” (from the medieval Latin vassallus, a servant) was not a low-born serf, but one who held land on condition of allegiance to a prince or king. The EU, by contrast, has not yet threatened to invade Britain in the event of regulatory divergence.

But “vassal” very quickly came to mean anyone in a subordinate position of power to another. Shakespeare calls himself a “vassal” to his lover as well as a “slave” in Sonnet 58, and Pope Pius V testily declared Elizabeth I a “vassal of iniquity”.

In the old language of international affairs, a “vassal state” was often obliged to pay money to its superior, and usually expected to provide military assistance on demand. It remains to be seen whether Jean-Claude Juncker really intends to appropriate our aircraft carriers.