I received my British passport, but all of my supporting documents have disappeared. Nothing has been returned six weeks after receiving the British passport, and HMPO cannot tell where the documents are or when or if they will be returned.
I ended up getting an emergency U.S. passport, which the Embassy could print same day (within one hour actually), as the U.S. requires me to enter on my passport. I will need to exchange for a full-validity passport within a year. I haven’t yet replaced my European passport, as I have an ID card. The U.S. Embassy told me that HMPO lose passports all the time.
Worst case, investigate the process of getting an emergency Canadian passport. So sorry this has happened to you.