With Britain's attention distracted by the virus, migrants have been redoubling their efforts to arrive in small boats from across the Channel.
Priti Patel, the Home Secretary, is already considering law and treaty changes to make it easier to return migrants.
Migration Watch said: “The numbers give a real taste of things to come if government succeeds in throwing open our jobs market to the world.'
The Migration Watch UK think tank warned that the immigration proposals could even drive numbers up.
Tens of thousands more migrants from outside the EU will be able to come to Britain in the biggest immigration shake-up for decades.
The news came as Home Office chiefs confirmed there would be a fortnight quarantine for arrivals.
More than 3,200 migrants have successfully made the crossing since 2018, according to research by Migration Watch UK.
A population rise equal to Leicester in the space of a year is not slow but eye-watering, said Migration Watch UK.