Italy from us through heathrow

To answer this kind of question, we always need to know if you are booked on one ticket to your final destination, or if you are changing to a different carrier entirely.
If you can provide all of the details you have (airlines, etc. if not gate info), you might be able to get some reassurance, but an hour and a half is definitely tight for Heathrow.
There is no easy way.

Yes, you have to go through security in Heathrow. You will likely land in terminal five and leave from there as well. It should be enough time, but that is the bare minimum at Heathrow. If you have one world status, or fly business class then you will be able to use Fast Track to get through security.

If this is on one ticket.....

Go to this website:

http://www.heathrow.com/flight-connections

fill in your flight information and you will get step by step instructions on what you will have to do.

Which terminal you arrive at depends on the airline you're flying. The same for departure.

You will have to go through security but it is a separate one for connecting passengers. There is no fast track at connection security.

If this is on two tickets, come back and let us know because the procedure is different and you probably won't make it in 90 minutes.

If on one ticket, follow the purple signs. We are experienced at Heathrow, but were jet lagged last year, and accidentally exited the airport. So Don't do as we did- follow the purple signs.
And yes, you will go thru another security checkpoint, but it usually goes quickly, at least in our experience.
Safe travels.

Thank you all.

April, we are flying business class. What do we need to do for the fast track

A couple of things to know would be helpful in giving advice… airlines? One ticket with boarding pass for second flight? Checked luggage or carry-on? We do business class on British Airways so I know that scenario.

Patty,

Yes one ticket AA operating for British airways. No check bags.

Boarding passes will be in hand

Again, there is no fast track security for connecting flights.

If you are flying on American, you will arrive at Terminal 3.

Where are you going in Italy and on what airline. If it's BA, you will either leave from Terminal 3 or Terminal 5.

The Fastrak for Business Class seems to be a thing of the past.

Fast Track security is only available for departing passengers.

It is not available for connecting passengers.

Flying to Florence in BA

You will have barely enough time.
LHR is a sh—show.

I've read every response and you certainly have a variety of input here :)

1. Without question, you will go through security again. Here is what you can do to be prepared in advance and not find your bags going over to the dreaded secondary screening line. First, maybe you put water in your water bottle after clearing security in US- dump it in advance of security. Second, electronics will need to go through separately. Third. Liquids in clear quart size bag that is removed from your luggage. Shoes stay on. Take off belts. Don't start getting ready for security when you are assigned a location/bin. Be prepared in advance.
2. Follow the purple signs and it will show you how to get to your transfer without needing to clear passport control.
3. Do your best to catch your flight, but have a "back up" flight list in mind. Any one world alliance carrier could be a possibility to get you onto Florence if you miss your flight.
4. Since you are flying on a British Carrier if they don't make the connection for you and you are delayed to your final destination by a certain period of time, they are required to pay you compensation but you must apply for it. https://www.britishairways.com/content/information/delayed-or-cancelled-flights/compensation scroll down to the bottom of the page where it says: "When you can claim compensation"

@Frank- yes there is Fast Track for connecting flights through terminal 5. I just did it last week and about a dozen times over the past two years.

@OP- when you get off the plane in Heathrow, follow the purple signs for connecting flights. When you get to the security checkpoint you will see a narrow passage on the right with the signs “Fast Track”. You will scan your boarding pass and get to the shorter security line. The longest this line has ever taken me was 15 minutes, but it’s usually more like less than 5 minutes. This is all in terminal 5 though, so be sure to look at the boards for which terminal your flight to Italy departs from. Your BA app will tell you which terminals you’re departing from. Also the flight attendants on BA are super helpful about navigating Heathrow.

Please use this link to get instructions on what to do:

http://www.heathrow.com/flight-connections

Your flight on AA arrives at Teminal 3. Your departing flight to Florence departs from Terminal 5. It is imperative that you understand how to get between terminals via airside bus. Any other way will guarantee you a missed connection.

Heathrow states you need 90 minutes for this transfer so it is tight. But if you miss the connection, BA has to get you on the next available flight at no charge. That means the next flight with available seats.

For a transfer, you don't need an ETA.

And be sure to use the bathrooms before getting off your flight, don’t stop in the terminal once you land, keep moving…and also keep checking the departure boards as you pass each one on the way to your next flight….just in case there is a gate change.
You don’t want to miss it.
Good luck.