Originally Posted by
flyerCO
I thought it more the setup of airport and fact that theres no exit immigration check in UK. If passengers were dumped into airside they'd be able to get away without going through immigration.
Just to clarify, there will be exit immigration at HEL for ARN-HEL (Schengen arrival) connecting to HEL-LHR (non-Schengen departure). The check takes less than five minutes, though, and there are automatic gates for holders of passports from certain countries (e.g., EU). There is no re-clearing of security. Overall, an hour connection is very likely doable.