The Identity and Passport Service offers guaranteed services at its public counters for customers who require a passport urgently. To provide this kind of service, it is necessary for customers to make an appointment to be seen.
Further reference:
24-hour Passport Adviceline: 0300 222 0000 (see terms and conditions). Calls made to 0300 numbers from landlines and mobile phones are charged to customers at their network provider's national rate. Live operators are available to assist with your enquiry 24 hours a day.