I have 2 UK passports. One I was using all the time would be rejected at LHR. I was chatting to the Border Force officers and they suggested that the photo was old and that was possibly causing some issues. They checked my other passport and suggested that I use that one as the primary. So far since doing that, I have had no issues with any of the e-gates in Europe or LHR. I was in the work uniform and the arrivals hall was not busy so they were happy to chat.
Last edited by redsnail; 6th Oct 2023 at 10:20.