Industry experts have issued a series of dire warning about the likely impact of mooted plans to quarantine arrivals in hotels for up to ten days.
Some travellers coming to England will have to quarantine in hotels, amid concerns about new Covid variants, the government is expected to announce.
Prime minister, Boris Johnson, is expected to decide after discussing the proposals with senior ministers later.
Most foreign nationals from high-risk countries are already denied UK entry so the new rules will mainly affect returning UK citizens and residents.
Quarantine rules are set by each of the UK nations but tend to be similar.
Ahead of the move, the World Travel & Tourism Council (WTTC) has said the introduction would force the “complete collapse of tourism as we know it”.
The concern follows nine months of devastating travel restrictions, which has left scores of businesses crushed, millions of jobs lost or put at risk, and confidence to travel at an all-time low.
Gloria Guevara, WTTC president, said: “The UK tourism sector is in a fight for survival – it is that simple.
“With the sector in such a fragile state, the introduction of hotel quarantines by the UK government could force the complete collapse of tourism.
“Travellers and holidaymakers would simply not book business or leisure trips knowing they would have to pay to isolate in a hotel, causing a drastic drop in revenues throughout the sector.
“From airlines to travel agents, travel management companies to holiday companies and beyond, the effect on UK travel businesses would be devastating, further delaying the economic recovery.
“Even the threat of such action is enough to cause consternation and serious alarm.”
WTTC said the tourism sector contributes nearly £200 billion to the UK economy.
The sentiments were echoed by Karen Dee, chief executive of the Airport Operators Association, the trade association for UK airports, and Tim Alderslade, chief executive of Airlines UK, the industry association representing UK-registered carriers.
In a joint statement, they said: “Less than two weeks ago the UK introduced some of the highest levels of restrictions in the world.
“Flights today are already banned from countries with high infection rates.
“Pre-departure controls mean anyone arriving in the UK has already tested negative.
“There is further quarantine upon arrival and the option of a second test.
“We have fully supported the government to do what is right in the face of this pandemic, but policy should be based on evidence and there must be a roadmap out of these restrictions as soon as it is safe.”
They added: “The impact of further measures would be catastrophic.
“They will impact vital freight and PPE supplies and jeopardise tens of thousands of jobs and the many businesses that depend on aviation.”