They were enforcing priority boarding today at LHR-LBA. Did priority by status- saw a couple then told they couldnt use the priority as not gold/silver etc
Then boarded by row. That was being enforced and they were stopping them all if not in the rows called. That meant the queue to board was full of those being made to wait and passengers had to thread past them in the corral.
Only 2nd bags were being tagged and the plane wasn't full so there wasn't an issue with hand luggage fitting in.