RCI, P&O among others sail from Southampton, BUT both have a minimum age of 12 months at time of travel. I'm sure other cruise companies have a similar policy. Regards.
Pand o brochure say they will provide a cot for infants over 6 months and under 2 years so I assume they do take infants.
I'll Say this again, read the T&C's on the P&O website. Brochures are history books, not current policies.
We cruised across the atlantic with Costa with a 6 month old and a 2 year old. Kids facilities on many many ships are great from 3+ but generally with a baby you will be looking after the baby all the time. On P+O the night nursery facilities are great for enabling you to have some you time in the evening. Dont be put off though, if you are a laid back parent and wont get stressed if your baby takes lots of trips round the deck to get to sleep etc you will have a great time. Look for something that has lots of dining options though because really small children and long 6 course dinners dont go together well. We did it for 3 weeks and had a lovely time and my children have cruised ever since but if its the whole formal dining thing you want then either wait for P+O or book a nice hotel with BB sitting.
Have a great trip..
I'm sorry but what you did in the past is no longer relevant. Read the T &C's on the company websites for what applies now.