Sorry for bumping an older thread but I wanted to share my experiences in case it's in any way useful to somebody else in the future, I'm not good at explaining so please accept my apologies for any grammar, spelling etc...
About 2 weeks back I used the online service (just like everybody else on the thread), everything went swimmingly well, had some slight issues with my photograph being rejected online due to lighting and I found that re sizing the photo in paint worked. A couple of days later I received the the email and text to say my application and photograph had been accepted and I would be receiving my passport soon.
A couple of days ago my shiny new passport arrives, which was less than 2 weeks (quoted 3 weeks). I was really pleased and quite excited to receive the new one.
It had been emphasised to me in email and text that I 'must' sign my new passport as soon as I receive it, which is what I did using a 'blue' ballpoint pen.
This morning I received an email and text from HM Passport Office reminding me to sign my passport in a 'black' ballpoint pen and automatically my heart sank and the anxiety kicked in. Nowhere in the initial correspondence did it say to use a black pen. So I did plenty of googling and found varied results on people experiences.
I phoned the passport office this morning and the young man told me that I would have to pay for another one (£80 give or take), I should explain we're a very low income family and this news was a massive hit.
After more googling and stressing I decided to phone them back and this time I had a different person, a lady, to whom I explained what I had done and is there anything that I could do to avoid having to pay for another one, she was very nice and went off to check some official stuff and came back to me with the line the passport office recommends black ink and nowhere in her documentation did it say blue ink would be rejected.
A massive relief for me and instant anxiety relief
The moral of this story is check everything carefully first and use a black pen !!
I hope this helps one person because there are a lot of people on Trip Advisor handing out misinformation