I am trying to figure out connection time and am wondering whether you can skip customs if you're flying from Rome to London?

No, you go through Italian immigration in Rome, then UK immigration/customs in London.

UK is not part of the Schengen common travel area.

If you are changing airports then you will have to pass through immigration, collect luggage & go through customs then recheck luggage & through security at the 2nd airport

If you are flying to London on a low costs airline or can't check your luggage through then you have to pass through immigration to collect your luggage, go through customs, then recheck your luggage & pass through security

If you are through ticketed or can check your luggage through then you can stay airside and not have to go through immigration though you will go through security & customs (yes the UK does have it airside)

In any case you have to follow the UK rules on hand luggage which can be found on www.baa.co.uk

ttt this is how to bring your post back up without repeating it.

Or if you lose it then click on your name and all your postings show up

hi PalenQ, I didn't mean to repeat it...I tried searching for the first one using my screen name and couldn't find it, so I thought for some reason it didn't go through. Apologies for that!

And thanks to everyone for the replies, I now know to include the requisite customs time for my connection.

Aha - I didn't know about the clicking on your screen name trick. I just put it in the search bar. Thanks again, alan!