Fun and games at LHR T3 on Sunday when a B2B TP Run LHR - SOF - LHR went a bit Pete Tong. Due to the Lizzy Line being held for 20+ mins (faulty doors) I had to bolt to security. BA890 scheduled to depart 13:20, clear security by 12:45. Puffing and panting I slammed my boarding pass down on the security gate scanner at 12:43 (based on BA's system). Red flash. Denied - return to check in. Between leaving home and getting to T3, BA changed the departure time to 13:15, so I missed conformance by 3 mins rather than making it by 2 mins

Check in agent made a call to try and get me through (since HBO) but there was no answer. She then mentioned the flight had moved back to 13:20 but it was well past conformance by this time, so her only offer was to pay £290 to change to another day. It was the end of her shift so she suggested calling the GGL as "they have more flexibility". 38 mins later GGL told me only the airport can deal with my situation.

New agent on the First counter who wasn't budging so I just paid to make the change but said I want to complain to the duty manager. Duty Manager couldn't do anything about a refund (but was shocked I was charged and paid) so I am dealing with that.

On to EC261, my reading is that I was IDB under Article 2, and I met Article 3(2). I've submitted an EC261 claim for €400 on this basis but suspect they will just blame security despite it being their temporary schedule change that caused missing conformance.

"denied boarding" means a refusal to carry passengers on a flight, although they have presented themselves for boarding under the conditions laid down in Article 3(2), except where there are reasonable grounds to deny them boarding, such as reasons of health, safety or security, or inadequate travel documentation.

Can't find similar posts / cases - any thoughts or experiences?