International travellers could face spot checks and £1000 fines if they fail to self-isolate for 14 days after arriving in the UK under measures to guard against a second wave of coronavirus.
Home Secretary Priti Patel is expected to outline the plans, which will be introduced early next month, at the Downing Street briefing on Friday.
Exemptions for road hauliers and medical officials will apply, while the common travel area with Ireland will be unaffected.
Arrivals from France will not be exempt, a senior UK Government official confirmed, following confusion earlier this week.
The plans come as official figures showed government borrowing has surged to the highest figure for any month on record, with swathes of the economy ground to a halt by the lockdown.
Travellers will be asked to fill in a form with their contact information, and health officials will perform spot checks to ensure compliance with the measures.
The quarantine period will apply to British citizens returning from abroad but plans will be reviewed every three weeks.
Ryanair boss Michael O’Leary earlier this week branded the plan “idiotic” and “unimplementable”, while trade body Airlines UK has previously said a quarantine “would effectively kill” international travel to and from Britain.
Many other countries already require arriving passengers to enter a 14-day quarantine, including New Zealand, South Africa, South Korea, Spain and the US.