Originally Posted by Bumpylanding
I will be flying VIE-LHR-SYD this Saturday. I was thinking of changing the VIE-LHR leg so I could arrive early and do a bit of a day trip (flight LHR-SYD is in the late evening). I don't believe I would be falling foul of any security rules but grateful for any advice to the contrary. Thanks!
I almost always leave the airport when I travel through LHR going east. Fly overnight, arrive LHR T3, tell the immigration person I will be visiting the UK for a few hours, go outside to the AC arrivals lounge, shower, eat, relax, walk back into T3, go though security, and off to the departure lounge or gate depending on circumstances.
I'm allowed to enter the UK as I please. If your passport doesn't give you that freedom you may face further obstacles.