I've had a UK biometric passport since 2014. Despite this, I have never been able to enter the UK via an electronic gate. Instead the gate always tells me to seek assistance. Last night, after returning from a European trip, I asked the immigration officer if there was a reason for this. Apparently, there is something on my file -- that is nothing to do with me -- that forces the gate to fail and sends me to speak to a person at immigration rather than using the gate. Apparently, the officer was not allowed to tell me what this thing was. However, I have no problem using electronic gates at other European countries.
I am a UK citizen, and do not have a criminal record. I regularly travel (roughly once every 2 months) and have never had trouble abroad. Nor can I think of any reason why I would otherwise be suspicious to UK immigration. Naturally I would like to use the e-gates to enter the UK as the referral to an immigration officer can often increase my wait time by 20 mins. Does anyone know what this thing on my file could be, and how I could change it?