Question to the Home Office:

To ask Her Majesty’s Government what conditions must obtain before a person’s passport can be confiscated or revoked.

The criteria for the issue, withdrawal or refusal of a British passport are set out under the Royal Prerogative, which is put before Parliament from time to time (https://www.gov.uk/government/speeches/the-issuing-withdrawal-or-refusal-of-passports). A passport may be confiscated or revoked if a person did not or no longer meets those criteria or if the passport is being used or suspected of being used for purposes which may be unlawful.