Is British Air baggage size for carry-on's interpretted literally?

Yes that means 22" including handle and wheels. I have never seen them weight a carry-on but they have scrutinized our carry-on bags closely. Fortunately they fit the requirement (we checked in advance to be sure).

BA has one of the more generous size requirements, 56 cm rather than 55 cm like most airlines. If you are ever going to fly one of the other European airlines you would be well advised to get smaller luggage anyway.

I will say for the first time last Sept they made my husband put his bag in the sizer (we've flown with them 4-5 times). Ours is 'carry on compliant' but is really pushing the boundaries (it's a 22" with the wheels - maybe even 22 1/2). We both used to travel with Atlantic luggage which was 21", but one of the wheels went faulty and we got a piece of Air Canada luggage. Because of the sizer issue, I just bought one of the RS carry on, and we can use our other piece of Atlantic luggage and scrap the AC one.

Airlines seem to have really gotten into the - 'well, it won't fit in the sizer by a smidge so you have to pay to check it' (more money for them). Apparently BA is also cracking down on the personal item...

http://onemileatatime.boardingarea.com/2015/07/31/british-airways-carryon/

The reason that they are so strict on this is that anything bigger will not fit in the overhead lockers. They have frames in the airports into which you drop the case. If it won't fit - into the hold it goes and you pay additional fees.

Thanks for the replies! I guess it is as I feared.

We won't have to pay for one bag checked in but there is the unpleasantness of having to deal with baggage claims plus the chance of lost luggage.

We might buy some RS roller bags. I thought we traveled light already, but would have to travel super-light.

It is going to become even tighter. BA and others have said that they are taking action because so many people recently have tried to beat the system and also avoid checking clearly oversize bags.

When they say "including handles, pockets and wheels" they really do mean it.

Note especially the final sentence in this quote from this morning's BBC News:

British Airways is to cut the hand baggage allowance for customers on
its flights, the airline has announced.

The maximum size of main carry-on bags will remain unchanged, but
smaller second bags such as handbags will be capped at 40x30x15cm, the
airline said.

It said there had been "an increase in customers travelling with hand
baggage that exceeds their allowance" in recent months.

The change will come into force "in the coming weeks", the airline
added.

Currently, passengers can board flights carrying one bag of up to
56x45x25cm, weighing up to 23kg, plus another bag up to 45x36x20cm.

A spokesman said the new guidelines - which apply to all customers -
meant the latter changing "ever so slightly".

He said overloading of hand baggage caused delays as staff removed
bags from the cabin. Last month, a teenager from Scotland collapsed
with heat exhaustion after wearing 12 layers of clothing to avoid
paying a £45 extra baggage fee.

James McElvar vomited and was given oxygen during the Easyjet flight
from Stansted to Glasgow.

The RS Roller Carry-On is 20 x 13.5 x 9 so it should easily meet the requirements. It does have one nice feature --- Zip-Out Expandability: Gain an extra 2 inches of cargo depth in a pinch (making it "fatter" than the carry-on limit, but perfect for checking).

I was thinking we could put our coats in the expandable section just after the baggage check and getting our yellow carry-on tags from British Air. Only a very modest cheat and we would be well under the volume sizing they require, just missing a bit on the width.

BA allows one free checked bag per person. Why not just check the bag and carry very little on? Then you have a lot less to schlep around the airport. It would be so much faster for everyone to board and deplane, and get on their way, if people stopped carrying all their stuff onto the airplane. Then you don't need to bother with new bags. Wray

Actually Wray that is what we are now concluding. We've always checked baggage in but thought we'd try to travel light this time. However, British Air is asking for a smaller bag then we now have. We still want to take a small flight bag in addition to a personal bag on the plane which will carry our essentials in the unlikely event that our luggage is misplaced. Have had a baggage handling error a few times in the past but they always turned up the next day at our hotel.

So as long as the RS tour will allow us to tuck away that flight bag, this is the new plan. I'll check with the RS people tomorrow to confirm this is OK.

Les, that's what I do. My present bag is a 20" RS bag, but I checked it. I still travel light because of all those times one needs to carry their bag up stairs, etc. Your bag is light/small enough for that as well. I just don't want to keep the bag with me if I don't have to do so. I too take a small bag for anything I can't lose, and a couple extra clothing pieces, and then I tuck it back in the suitcase when I meet up with it again. I bought down from my 22" bag to carryon, but then saw no point in carrying when I didn't have to do so. So I say you're on track!

Wray, that is a good idea instead of our flight bag. I could take my old RS Civita day pack which collapses quite small for temporary transport in the air. So I could have (1) my Pacsafe bag for under the seat stowing, and (2) my Civita day pack for storing in a luggage bin.

From the British Airways website:

"If you purchased a fully flexible Y class fare before 11 August, your allowance will remain two pieces, even if you are due to travel after 11 August. In this event, we recommend that you print off your original e-ticket receipt and bring it with you to the airport as proof of your baggage allowance."

So this won't help for future trips. But if you have already purchased your tickets, they will (supposedly) honor the prior guidelines.