Now I'm very much aware that Northern Ireland is part of the United Kingdom and those who live there have British passports.

If I travel from England to Northern Ireland by car ferry, do I need a British passport and do I go through 'UK Boarder Control' ?

Just thinking of having a few days away, and I've been all around the world but never been to NI so was thinking I might give it a try 😀

Would I be better to fly and just rent a car rather than driving about in an English registered vehicle ?

There will be no border control to NI. Great Britain, the entire island of Ireland (North and ROI), the Channel Islands and Isle of Man are all part of the Common Travel Area which does not require passport for travel between members. 
 

Travel advice says you need ID (doesn’t have to be a passport) when arriving in Ireland (ROI) from the UK by air, but otherwise you shouldn’t see any border controls or passport checks. 
 

If you don’t have a passport you don’t need to get one just to visit NI. If you have a photo ID driving licence that would probably suffice as ID to visit ROI too. 

27 minutes ago, alexp999 said:

If you don’t have a passport you don’t need to get one just to visit NI. If you have a photo ID driving licence that would probably suffice as ID to visit ROI too. 

Just renewing my passport now, but you can never be sure how long it takes.

Tomorrows job is to fit my new Yuasa battery if the weather is dry.

11 hours ago, unofix said:

Just renewing my passport now, but you can never be sure how long it takes.

Tomorrows job is to fit my new Yuasa battery if the weather is dry.

I have another thread on passports but can't find it right now, I renewed my UK passport last month. I did it online on a Tuesday, and had the new passport in my hand on that Friday!! Yes, I was shocked too after hearing about all the delays people have had recently. I never expected it to take just 3 days!!

Oh, I too had my battery replaced this week with a Yuasa! That's a coincidence!

Oh, and shame on you never having visited the most beautiful of countries LOL

Just found my 'passport' thread...

 

Nothing to do with passports (quite normal for threads on here 🤣) but I've got my new battery fitted 👍

 

12 minutes ago, unofix said:

Nothing to do with passports (quite normal for threads on here 🤣) but I've got my new battery fitted 👍

That is one big battery! On Halfords web site, there are 2 batteries listed for my car, one, is the physical size of yours (no mission of fitting in the battery space on my car), and the other is the one that eventually was fitted. I'm guessing there's a reason that Ford chose to locate it half way under the scuttle panel making it very awkward to fit, maybe weight balance?