The Passport Office is so "inundated" with calls that "you can't speak to anybody", a frustrated member of the public told ITV News today.
Speaking outside the headquarters in Liverpool, another told ITV News the only option available to book a renewal appointment was in Belfast.
The Home Office has outlined how people who are facing delays to their passport renewal can get it fast-tracked for free.
If you are worried about your passport application not being ready ahead of your holidays, there are a few options available to you.
Photos shown to ITV News appear to reveal the scale of the backlog at the Passport Office, amid staff claims of "blind panic".