Can I refuse a telephone interview that takes place without prior notice?

If you receive a phone call at the worst possible moment, you can and should ask to reschedule the appointment. However, you should proactively suggest alternative times straight away and also ask how long the call is likely to last. If, on the other hand, you are well prepared and have enough time for an impromptu telephone interview, there is no reason not to go ahead with the call and use it to demonstrate your competence and self-assurance.