Brits befuddled by who or what is Tim Hortons

Famed for its coffee and doughnuts, Tim Hortons is an institution in Canada.

Now the restaurant chain is expanding to the UK - but British consumers, it seems, have a lot to learn.

On the streets of London, the terms "double double" and "Timbit" baffled most people the BBC spoke to. So we asked Canadians to explain the appeal.