I'm planning on going to the UK for a new passport. Would like to return quickly so I noticed a system that if you

apply for a passport online, then you have an option for the "Fast Track" method. That is apply online, receive a code,

enter the code, and can get an appointment for the next day to have a 5-10 minute meeting at the passport office.

After the meeting, if goes well, a new passport will be available to you after 5-6 days.

Anybody know what meeting is about?

Or would there be another way to get a new PP quickly? 3-4 weeks is average time for normal applications?

There are 1 day or 1 week options. See all the information you need online at https://www.passport.service.gov.uk/filter/service-selection