Oftentimes, when travelling between the UK and Canada, I find it cheaper to make a connection in the US. Travelling to Canada is straightforward if I use my Canadian passport, as I don’t need an ESTA for my US connection.
What I am wondering about though is the return leg. I would obviously enter the UK with my British passport, however checking in with this passport will require me to have an ESTA to enter the US. However, checking in with the Canadian passport may cause difficulty when it comes to my entry into the UK, given my previous BRP is linked to that passport.
Given that I go through CBP Preclearance in Canada, am I able to check in with my British passport and present my Canadian passport to CBP? Failing that, is there another way I can take this itinerary without an ESTA or other immigration-related grief?