I applied in-person. The process took 1 day. I interviewed at Subway (Birmingham, England) in May 2016
Interview
The interview was with the store manager, it was very simple, he just wanted to know my experience as cashier and serving people, as I worked before in a restaurant he though everything would be easy for me so I got the job directly.
He even wanted me to start working the same day.
The worst thing was having to do a 5 days unpaid training, which finally ended up being 6 days, 25 hours for free.
I interviewed at Subway (Barnsley, South West England, England)
Interview
I was sat down and asked questions about myself in a possible manner in the middle of the restaurant as people dined around me. I was then instructed to cut bread so they could see how well I could do.
Easy flow, face to face and they are quite patient with you. The manager are understanding if it's your first time and let you through the flow of the process
Very simple and straightforward. Normal questions like availability, have you worked in food service before, etc. I think it depends on location though since friends at other locations have had more substantive or less substantive interviews.