My situation:
I hold two citizenships, Pakistan and British.
I was refused a US visa back in 2011, then was approved later last year and it is valid for the next 5 years.
I already have an answer here.
Based on that answer I will use my Pakistan passport to travel to NY. Now I am planning to visit Canada as well. I am planning to cross border by driving. As I understand, being British Citizen means I can just enter without a visa if passing through a road border.
I don't want to apply for a Canada ETA because it will be refused as I have had US visa refusal back in 2011.
Question
If I use my Pakistani passport to enter the US, can I still use my British passport to cross the border, or I will be asked which passport I used to enter the US? (Because I cannot use Pakistani passport as I will require visa)
Or, if I can use my UK passport, will they ask me if I have valid ESTA or Visa in the UK passport?