Yes you can but you can buy alcohol by filling in a form in your cabin prices are usually £12 for a litre bottle of whiskey. You can bring alcohol onboard when you dock at a port. Usually 3to 4 days b3efore the end of the cruise you can buy a bottle for about £8 onboard ship.
By the shed load! Was in the caribbean last year on this ship and we bought a bottle of rum at each port - and drunk them all, I seem to remember.
Yes you can. P&O reserve the right to confiscate alcohol in the event of a passenger being worse for wear.
P & O certainly aren't keen on you taking alcohol on board, although whether it would be taken off you I'm not sure! We have always found their prices to be pretty good compared to what we pay here in a city so it's never been an issu.