Heathrow security
I am going from ARN (on SK) to SFO (on UA) via LHR. If I remember correctly the SK flight arrives at T3(?) which is the same terminal as the UA flight to SFO departs from. I just heard a rumouer that even when you are on transit at the same terminal, you have to go through a new security screening at LHR.
Anybody on this experienced forum who knows the facts?