Siri: "I'm sorry Tom, I'm afraid I can't do that."

Another handy iOS 7 workaround, this time for iPhone: If you've had the experience of Siri refusing to dial a number he (or she) has always happily dialled in the past the reason is the number stored in your contacts is now too short for the nasal ninny. Edit the contact to add an extra zero at the end of the number to get around the bug.