Originally Posted by emma69

Please tell someone you are not continuing your journey when you get to London. Otherwise every other passenger on the flight will have to wait while they page you, page you again, then try to find your bags to offload them.

Also, if you didn't tell them until the flight departed, you would be sitting around the airport for hours (assuming you had at least 2 hours connection time, plus all the time it will take to reunite you with the bags etc.)