What to tell potential employer about interview already booked

[Narcos]

I have 2 interviews lined up, one on Wednesday for a temporary position and another a week tomorrow for a permanent job. I know they are looking to fill the temporary position quickly - what should I say if I get offered the job and start date before the other interview has taken place? Should I tell them I have another interview to go to for a permanent job or tell them a white lie.....that I have a doctor/hospital appointment?

Tricky. How likely are you to get the permanent one do you think? Unless you think it’s very likely, I personally would tell a white lie - I wouldn’t want them to think I was ready to leave before I’d barely even started. But I tend to play things close to my chest in general...

I'm feeling pretty confident about both interviews. They are both a close match to my skills and have been preparing for the interviews. Think I will go the white lie route anyway.... Some appointment for for kids that I can get out of sounds like a good bet.