Theoretically none because they are both in the UK. However, because of increased security in recent years, many operators are insisting on photo ID. Check with the ferry company to be absolutely certain.
yes you do in order to travel you must have a passport
Learn to and then prove that you can drive a car, once you have done this they send you your photo id
Probably photographic identity such as a passport or suitable driving licence. Requirements depend on the ferry company.
Yeah you should have an id with you, it is very rarely chance that if someone ask you for your id... better to have
Check with the ferry operators
If you fly, the airline will request some form of ID. Currently the ferry companies don't require ID. There is no legal requirement for passports between the ROI and the UK.
Strictly speaking, you won't need any ID to get on the ferry from Portsmouth to Guernsey. However, if you are not a British citizen, it might be best to take your passport with you.
No, it is part of the UK.
Probably, if has photographic identification. Check with the plane or ferry operator.
No but you do need photographic ID for both the plane and the ferry, eg passport , drivers licence, citizen card.
No but photo ID is a good idea.
No unless you are coming from France but you may need photographic ID and some flight/ferry operators may demand to see your passport so you check with them before travelling. Source: Jerseys government website