I am an EU citizen and don’t have a passport right now. Was booked on BA905/BA834 (FRA-LHR / LHR-DUB) today, and triple checked that I am allowed to do air transit with my id card as travel document. Gov.uk says no eta needed, not entering the UK, staying inside T5. I called the GGL hotline before my card expired, and they confirmed this is fine. The gate agent was not to be convinced, however, and as a former GGL now Silver I am only provided with a phone number that works Mo-Fr 9-18. Awesome experience all around. I am now stuck in Frankfurt. Has anyone else experienced that?