I flew YYZ to LGW in November around 7 years ago. The Captain mentioned he wanted to delay departure as due to the jet stream he; "didn't want to be sitting on the ground at Gatwick waiting for a gate." We took off fairly shortly as it happened and did the flight in just over 6 hours (take off to landing) which is the quickest I've ever done it in scores of flights over 40 years.
Not as quick as the OP, but very welcome.