What happens if I need to go from one port/airport to another in the UK to be able to get transport back to the Bailiwick?

Public transport can be used if there is no other option – for travel from your place of arrival in the UK (port, airport or station) to your place of departure (port or airport) to travel back to the Bailiwick; or for travel from your place of arrival in the UK to overnight accommodation (if you have to stay overnight) and onwards to your place of departure (port or airport) to travel back to the Bailiwick. If using public transport, you must wear something that covers your nose and mouth and stay 2 metres away from others. If you have coronavirus symptoms, you will not be allowed to travel by public transport and will need to demonstrate that the accommodation where you will self-isolate is safe.