Can I get to Germany from Norway with a single entry Schengen visa while having a flight transit in UK?

I have a single entry visa to Schengen countries(type c). I will be traveling to Norway from Toronto, Canada. I will stay for a week, then I will travel to Germany. My flight from Norway to Germany will have a transit in London. Will this be a problem with my Single Entry Visa? Will I be able to enter Germany even if I have a transit in London?