Just flew VCE-LGW-DFW-SJC on Saturday. The UK rules are the same as they have been for the past year or so and it has NOTHING to do w/your carrier, its airport enforced and quite simple. If your plane takes off from England - either as your first destination or as a transfer passenger - you may only have one small carry on. It is a rule strictly enforced. The only exception are those duty free items you purchase at the UK airport.
So while you may be able to carry on two pieces on your flight from FCO-LHR, when you get to LHR you will have to check one at LHR, which can be a time consuming process.
However, the AA flight you note in your title will be fine w/two carry ons.
Last edited by bdemaria; Jul 5, 2007 at 7:07 am
Reason: add'l information