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...