Have you checked the on time record of your incoming flight? Where are you flying from - and how oft

They now have my trans-Atlantic AA flight arriving London Heathrow at 9:30 AM; then connecting to a BA flight to Rome, which leaves LHR at 10:35 AM. They show Terminal 5 for both flights, but, before I call AA, is this really enough time?
The only thing you have in your favor is that flights from the US often arrive early due to the prevailing tailwinds. However, Terminal 5 is a real bear - endless corridors and escalator to get from anywhere to anywhere else.
Since you are connecting to Rome you won;t have to go through Immigration - BUT - if you plane is at all late by the time you wend you way off it you will be entering the terminal at about the same time that your ongoing flight is closing the doors.
My understanding is that legal connection time at LHR is 2 hours. I've barely made connections (staying airside) that were 2.5 hours - jogging with carry-on only - but changing terminals and having to go through security again.
Have you checked the on time record of your incoming flight? Where are you flying from - and how often does it delay flights - esp at the time you will be leaving? 9:30 is well into the day - and you can count on the airport being mobbed car rental companies in italy - it's not like arriving at 6 am.
It doesn't take 2 hours to connect within terminal 5, but you must clear security even to change from one gate to another, which is a pain. Minimum connection within Terminal 5 is 60 minutes, and if you are coming from one BA flight to another (even if the flight has an AA flight number), things go very smoothly. There are some real Heathrow pros on these boards, so I think you'll get some good advice, but my experience was pretty seamless (for a Heathrow transfer, that is).
I'm leaving from Northern California, and my itinerary is now showing car rental companies in italy SMF to LAX to DEN to LHR to FCO ... hah! Maybe, with some polite whining on the phone to AA, I can get rerouted through DFW, cut out at least one extra stop, and not have to plan sprinting through an unfamiliar terminal.
car rental companies in italy I have twice had to make an unplanned short connection via that route and found the staff more than helpful in responding car rental companies in italy to a request for priority in security. Polite desperation seemed to be the most effective way of communication.
Probably NOT enough time... because the lines for Security are LONG, even if you're traveling business class and have a Fast Track pass. Check out later flights to FCO and see if BA will protect you on one of them.
The reason it is probably not enough time is that they close the gate 20 minutes before the departure time. We had that happen to us in March where we figured an hour in the same terminal no problem! Then when we got through security (after being very assertive about being in the priority line) with 23 minutes left of our hour they were announcing final call for our flight. We ran but made it.
Varies depending on terminal and whether domestic flights are involved. 2 hours would be a T4 International to T5 Domestic which is the worst connection, other connections have connection times as low as 65 minutes - T5 international to T5 international