score:7
As you are departing from the UK, which is still in the EU for now, you benefit from Flight Compensation Regulation 261/2004, commonly known as EU261, which requires the airline to provide assistance in case of delay, and possibly compensation if you arrive (very) late at your final destination (unless it's not their fault).
What exactly you are entitled to depends on the exact circumstances (how late you are, how long you have to stay), but you can expect that:
If you get at your final destination over 4 hours late, you will also be entitled to a 600 euro compensation, unless it's not their fault (ATC strike for instance).
Note that EU261 will not apply for the return flight as it's neither an EU airline nor a flight departing from the EU, however many of things (hotels and meal vouchers) still hold via other regulations (but usually definitely not the compensation).
Upvote:5
I can tell you what happens when no EU flight segment is involved, as this should be the worst case.
Air Canada once sold me a Zihuatanejo->Mexico City->Toronto flight with a mid-afternoon 45 minute layover in Mexico City, including a terminal change, that I knew was blatantly impossible to make. As all other possible routes involved either a red-eye flight (which I dislike) or an overnight layover somewhere at my expense I bought the ticket they offered anyway. When I missed the connection Air Canada rebooked me into business class on the next flight out and, since that was the next morning, gave me hotel and meal vouchers for the airport Marriott. I have also gotten hotel and meal vouchers from Air Canada when my flight was cancelled (at SFO) due to equipment issues and they couldn't get a replacement plane there until the next morning.
While I think I've had more issues with Air Canada than other airlines I've flown frequently, if you are flying on an Air Canada ticket they are fairly reliably forthcoming with help to fix, at their expense, the things they have screwed up. I've never been offered cash but they are generous with vouchers and make hotel reservations when you need that. That said, if your inbound flight arrives on time I also think a one hour international-to-international connection in Toronto terminal 1 is quite doable. Your luggage should be forwarded directly to the outbound flight and there is a separate, generally queueless, immigration channel for connections that should keep you airside.