Generally if you get turned away at the destination then the airline is liable for taking you away, so they won't let you fly unless they're sure that you will be accepted at the destination country.
Under UK legislation as the owners, agents or operators of a ship or aircraft you may become liable for a charge of £2,000 for every passenger arriving in the UK without:
- a valid “immigration document” which satisfactorily establishes identity and nationality or citizenship.
- and, if the person requires a visa, a visa of the required kind or other permission to travel. This visa, or permission, may now be in either physical form, or a digital e- Visa; or
- a valid Electronic Travel Authorisation (ETA), if the person requires one.
Under UK legislation as the owners, agents or operators of a ship or aircraft you may become liable for a charge of £2,000 for every passenger arriving in the UK without:
- a valid “immigration document” which satisfactorily establishes identity and nationality or citizenship.
- and, if the person requires a visa, a visa of the required kind or other permission to travel. This visa, or permission, may now be in either physical form, or a digital e- Visa; or
- a valid Electronic Travel Authorisation (ETA), if the person requires one.
https://www.gov.uk/government/publications/document-checks-a...