I'm travelling from the UK (non-Schengen, Heathrow) to Finland (Vantaa). I have a very brief transfer window and I've noticed on Flight Radar that the flight is always nearly late by 20 minutes, which cuts it a lot shorter. I have a connecting flight from Helsinki to Oulu, and I am 100% sure I have to go through at least passport control but I'm not sure about security too. I only have carry-on luggage but it could still take precious time.
The Finnair website seems a bit ambiguous about it, making it sound like I only need to go through passport control, or through security if I'm travelling TO a non-Schengen airport, but doesn't mention flying in FROM one.
Could someone enlighten me on this? I'm stressing pretty hard.
I already have boarding passes for both.